Winform : Binding et Rowstate de DatasetRésolu

Question

Salut tout le monde,

Alors voila mon pb j'ai une form dans laquelle j'ai un datagrid qui est rempli par un dataset(lui-meme rempli par un DataAdapter)

je ne veux pas saisir directement dans le datagrid...
je veux pouvoir saisir dans des textbox sous mon datagrid...
pour cela j'ai fai du binding sur mon dataset comme suit :

//On affecte le Ds au datagrid
dg_Liste1.DataSource = ds.Tables["T_USER"];

//Databinding sur les textbox
txt_code.DataBindings.Clear();
txt_code.DataBindings.Add(new Binding("Text", ds.Tables["T_USER"], "USRCOD"));
txt_nom.DataBindings.Clear();
txt_nom.DataBindings.Add(new Binding("Text", ds.Tables["T_USER"], "USRNOM1"));
txt_prenom.DataBindings.Clear();
txt_prenom.DataBindings.Add(new Binding("Text", ds.Tables["T_USER"], "USRNOM2"));
cbo_groupe.DataBindings.Clear();
cbo_groupe.DataBindings.Add(new Binding("SelectedValue", ds.Tables["T_USER"], "GRPNUM"));

la quand je clique sur une ligne de mon datagrid les valeurs apparaissent bien dans mes textbox et combo...

seulement voila lorsque je valide (avec un DataAdapter.Update(ds, "T_USER");) j'arrive bien à faire mes insert, delete mais PAS l'update.

Après vérification le rowstate de mon dataset ne change pas pour les lignes que j'ai modifié dans mes textbox....
la requête est bonne mais de toute facon, il n'arrive même pas jusque là puisque le rowstate n'est pas à Modified.....

alors qu'il est correct pour les lignes supprimer et insérer...

je pense que cela vient de mon binding....

en clair si je modifie mes valeurs dans mes textbox, l'info n'est pas mis à jour dans mon dataset.....

voila si quelqu'un à une idée....

@+
Arthenius

"Ce qui ne me tue pas, me rend plus fort..."

taoetc · Answer

un petit truc, enfin tout dépend comment tu as fait tes classe

mais tu dois pouvoir faire  : 
ds.T_USERTable

et tes bindings,
txt_code.DataBindings.Add(new Binding("Text", ds.T_USERTable,"USRCOD"));

C'est quand meme curieux que le binding fonctionne dans un sens mais pas dans un autre 
question béte , ta datagrid est t'elle en readonly?

Autrement, quand tu changes de ligne dans ton tableau, fait un truc du genre  ds.USERTable[datgrid.CurrentRowIndex].BeginEdit;

C'est peut etre la la cause du problème, peut etre

Autrement tu peux pmettre ta grille en acces et faire tes biinding sur tes colonnes,( si celle ci sont voués à etre fixe.

Arthenius · Answer

bon pour le nommage du dataset, on utilise pas les ds nommé, donc pas de DS.T_USERTable....
mais bon le ds.Tables["T_USER"] est plus long a taper mais c la meme chose...

la datagrid est en readonly effectivement, mais son passage en lecture ecriture ne change rien....
d'autant que le readonly empeche juste la saisie dans le datagrid..mais pas la lecture ecriture dans le dataset...

pour le beginEdit....ok mais je mais ou mon endinit???
vu que je peux selectionner un enregistrement par click, navigation pageup, etc...fleche haut bas...
bref....

ben oui a priori le binding marche pas forcement dans les 2 sens...
je trouve ca louche aussi...

j'ai fais un autre test, je modifie un de mes champs je click sur ma datagrid et je reselectionne le champs et la miracle de la technologie si je valide le champ est modifier....

a priori il remet a jour le dataset par rapport a mes textbox qd je clique sur le datagrid....

par contre je n'est pas compris ton histoire de mettre en acces ma datagrid et faire le binding sur les colonnes...c'est ce que je fais deja non ???

Arthenius

"Ce qui ne me tue pas, me rend plus fort..."

taoetc · Answer

On va commencer par la fin, tu fais ton binding sur ta datatable  et non sur ta datagrid.

Sur la datagrid , ca donnerait un truc du genre :
txt_code.DataBindings.Add(new Binding("Text", datagrid1[indexcolonne1], "Text"));
A mon avis, le binding que je t'indique ne marche pas, mais bon, c le principe : lié une cellule à un text box ,

Pour le readonly, je pensais que le fait que ta datagrid soit lié à ta table, cela fait que l'un verrouille l'autre. Parce qu'en mettatn ta datagrid en lecture ecriture, tu peux bien modifier les valeur et si tu fais ton update , ca doit fonctionner.

Si tu ne sais pas où mettre ton EndEdit, cela veut donc dire que tu n'as pas de bouton du style update , donc ,  la solution serait peut etre de mettre ton EndEdit sur le CellChanged

 un truc du genre :


int currentOldChange = 0;

public void CurrentCellChanged(....)
{
ds.Tables["USER"][CurrentOldChange].EndEdit();
currentOldChange = datagrid1.currentRoxIndex;
ds.Tables["USER"][datagrid1.currentRoxIndex].BeginEdit();
}

Ca peut peut etre fonctionner, m^me si ca fait quand meme bidouille

Autre idée, faire  un AcceptChanges sur ta datatable  avant ton update.

Bon voila, bon courage

Arthenius · Answer

j'ai fais le test avec le readonly et si tu modifie dans le datagrid les zones oui ca fonctionne...
mais je veux pouvoir saisir dans mes textbox....et la meme si le datagrid est en lecture ecriture...ca update pas...

pour le binding...ok j'avais pas compris ca comme ca....
je vais essayer de lier mes textbox aux cellules du datagrid....
mais bon les cellules du datagrid depende du dataset....
donc je pensais qu'entapant la source....

enfin si la prog etait une science exacte ca se saurait...

pour ce qui est du beginedit je pourrais peut etre le faire sur des textbox changed...

a voir et mettre le endedit avant mon dataadapter.update...

pas contre l'acceptchanges() je pensais que ca disais au dataset ok tu considere tout comme = à la base....

j'va voir tout ca...
merci...

Arthenius

"Ce qui ne me tue pas, me rend plus fort..."

Arthenius · Answer

merci taoetc...
c'etait bien le beginedit et endedit qui n'allait pas...


int currentOldChange = 0;

private void dg_Liste1_CurrentCellChanged(object sender, System.EventArgs e)
{
ds.Tables["T_USER"].Rows[currentOldChange].EndEdit();
currentOldChange = dg_Liste1.CurrentRowIndex;
ds.Tables["T_USER"].Rows[dg_Liste1.CurrentRowIndex].BeginEdit();
}


alors meme si c "artisanal" (bidouille c un peu fort)

ca marche comme ca....

alors je prend :o)))

merci...

Arthenius

"Ce qui ne me tue pas, me rend plus fort..."

taoetc · Answer

Enocre un petit truc que j'ai trouvé et qui peut peut etre de faire plein de bidouille :

  
4. Windows Forms Data Binding FAQ Home 
   4.1  Does MySql work with ADO.NET? 
   4.2  Where can I find a discussion of databinding and windows forms? 
   4.3  How do I test for a null value in DataView.RowFilter? 
   4.4  I don't have SQL Server. Is there any way to run the samples that need SQL server? 
   4.5  How can I programmatically move through a dataset that has bound controls? 
   4.6  When I try to update a dataset I get an error that the system is unable to find "Table"? 
   4.7  How can I bind an ArrayList to a DataGrid? 
   4.8  When I try to bind two comboboxes to the same datatable, both boxes show the same values, changing one changes the other. How do I make them have distinct values? 
   4.9  How do I bind a mdb file to a datagrid? 
   4.10  How do I bind a listbox or a combobox to a MDB file? 
   4.11  In my databound ComboBox, how do I set the SelectedItem property? 
   4.12  Are server side cursors supported in .NET? 
   4.13  I am populating a ListBox by binding it to an ArrayList. The initial display is OK, but later changes to my ArrayList are not shown in my ListBox. How can I get the changes to show properly? 
   4.14  My SQL server runs on a non-default port. How can I specify this port in my connection string? 
   4.15  What is a DataSet? 
   4.16  How do I add updating support to a dataset? 
   4.17  How can I import a CSV file into a DataTable? 
   4.18  How can I prevent a ComboBox and DataGrid bound to the same DataTable from sharing the same current position? 
   4.19  I get a 'This would cause two bindings in the collection to bind to the same property' error message. What might cause this? 
   4.20  How do I bind a TextBox to a nested relation? 
   4.21  How do I call a SQL stored procedure? 
   4.22  I programatically change a bound TextBox value, but the value does not get pushed back into the bound datasource. How can I make sure the DataSource is updated? 
   4.23  Why does the CheckedListBox lose checked state when placed in a tab page that gets hidded and shown? 

4.1 Does MySql work with ADO.NET?     

MYSQL can be used with ADO.NET. There is more information available here: 

http://www.mysql.com/articles/dotnet/
 

4.2 Where can I find a discussion of databinding and windows forms?     

Take a look at the Microsoft KB article, INFO: Roadmap for Windows Forms Data Binding (Q313482). This article gets you started. It also lists other Microsoft KB articles that have to do with using the Windows Forms DataGrid and databinding. 
 

4.3 How do I test for a null value in DataView.RowFilter?     

You can use the IsNull operator. 
 
[C#] 
 
     //the outer quotes are double quotes and the inner quotes are 2 single quotes 
 
     //Fax is the column mapping name 
      this.dataView1.RowFilter "IsNull(Fax, '') ''"; 
 

 
     // for a numeric null in custNo (suggested by Bob Gibson) 
      this.dataView1.RowFilter "IsNull(custNo, 0) 0"; 
 

 
[VB.NET] 
 
     'the outer quotes are double quotes and the inner quotes are 2 single quotes 
 
     'Fax is the column mapping name 
      Me.dataView1.RowFilter "IsNull(Fax, '') ''" 
 

 
     ' for a numeric null in custNo (suggested by Bob Gibson) 
      Me.DataView1.RowFilter "IsNull(custNo, 0) 0"
 

 

4.4 I don't have SQL Server. Is there any way to run the samples that need SQL server?     

You can use MSDE, a SQL server compatible database engine that MS makes available for free. You can download and install MSDE from a whole variety of sources. Here is one source. 

MSDE also comes with Visual Studio.NET / .NET framework SDK. It is available under $(VS Install drive):\Program Files\Microsoft Visual Studio .NET\FrameworkSDK\Samples\Setup\msde. You can then run $(VS Install drive):\Program Files\Microsoft Visual Studio .NET\FrameworkSDK\Samples\Setup\configsamples.exe to configure the northwind database that the samples use. 

 

4.5 How can I programmatically move through a dataset that has bound controls?     

You have to access a property called the Binding Context and then retrieve the BindingContext associated with the dataset and data member that you used for binding. After you have access to this object you just set the position property. You can move backward and forward through the dataset.

Download a working sample that shows this: simpledata5.zip 
 

 
form.BindingContext[this.dataSet, "Customers"].Position -= 1; 
 

 

Remember that when you scroll through the dataset all associated controls will scroll since they all depend on the same context. This is useful if you want to have several controls that display sections of a row operate in tandem.

 

4.6 When I try to update a dataset I get an error that the system is unable to find "Table"?     

Are you calling Update on the dataset like this without specifying the name of the table that you are updating. The problem is that when table names are not given the system assumes a table name of 'Table'. This of course causes the update to fail.

 
this.dataAdapter.Update(this.dataSet);
 

If so just change this line to 
 
this.dataAdapter.Update(this.dataSet, "Customers"); 
 
// replace 'Customers' with the table that you have
 

 

4.7 How can I bind an ArrayList to a DataGrid?     

Here is a technique for binding an arraylist of objects where the objects contain public property that can appear as columns in the datagrid. In this example, the object contains 2 public doubles, one named value and the other named sqrt. To bind this arraylist to a datagrid, add a custom tablestyle that has a MappingName of "ArrayList", and then use the property names as the MappingName for each column. Below are some code snippets. You can download a working project that also has code to delete rows and add new rows to the bound arraylist. 
 
private void Form1_Load(object sender, System.EventArgs e) 
 
          { 
 
               CreateArrayList(); 
 
               BindArrayListToGrid(); 
 
          } 
 

 
          private void BindArrayListToGrid() 
 
          { 
 
               dataGrid1.DataSource = arrayList1; 
 

 
               //create a custom tablestyle and add two columnstyles 
 
               DataGridTableStyle ts = new DataGridTableStyle(); 
 
               ts.MappingName = "ArrayList"; 
 

 
               int colwidth = (dataGrid1.ClientSize.Width - ts.RowHeaderWidth - SystemInformation.VerticalScrollBarWidth - 5) / 2; 
 

 
               //create a column for the value property 
 
               DataGridTextBoxColumn cs = new DataGridTextBoxColumn(); 
 
               cs.MappingName = "value"; //public property name 
 
               cs.HeaderText = "Random Number"; 
 
               cs.Format = "f4"; 
 
               cs.Width = colwidth; 
 
               ts.GridColumnStyles.Add(cs); 
 

 
               //create a column for the sqrt property 
 
               cs = new DataGridTextBoxColumn(); 
 
               cs.MappingName = "sqrt"; //public property name 
 
               cs.HeaderText = "Square Root"; 
 
               cs.Format = "f4"; 
 
               cs.Width = colwidth; 
 
               ts.GridColumnStyles.Add(cs); 
 

 
               dataGrid1.TableStyles.Clear(); 
 
               dataGrid1.TableStyles.Add(ts); 
 
          } 
 

 
          private void CreateArrayList() 
 
          { 
 
               arrayList1 = new ArrayList(); 
 

 
               //add some items 
 
               Random r = new Random(); 
 
               for (int i = 0; i < 20; ++i) 
 
                    arrayList1.Add(new RandomNumber(r.NextDouble())); 
 

 
          } 
 

 
          //create a struct or class that defines what you want in each row 
 
          //the different columns in the row must be public properties 
 
          public struct RandomNumber 
 
          { 
 
               private double number; 
 

 
               public RandomNumber(double d) 
 
               { 
 
                    number = d; 
 
               } 
 

 
               public double value 
 
               { 
 
                    get{ return number; } 
 
                    set{ number = value;} 
 
               } 
 

 
               public double sqrt 
 
               { 
 
                    get {return Math.Sqrt(this.value);} 
 
               } 
 
          }
 

 

4.8 When I try to bind two comboboxes to the same datatable, both boxes show the same values, changing one changes the other. How do I make them have distinct values?     

Make sure the two comboboxes use different BindngContext objects. 
 
     BindingContext bc = new BindingContext(); 
 
     this.comboBox1.BindingContext = bc; 
 
     comboBox1.DataSource = _dataSet.Tables["orders"]; 
 
     comboBox1.ValueMember = "CustomerID"; 
 
     comboBox1.DisplayMember = "CustomerID"; 
 

 
     bc = new BindingContext(); 
 
     this.comboBox2.BindingContext = bc; 
 
     comboBox2.DataSource = _dataSet.Tables["orders"]; 
 
     comboBox2.ValueMember = "CustomerID"; 
 
     comboBox2.DisplayMember = "CustomerID";
 

 

4.9 How do I bind a mdb file to a datagrid?     

You can use the classes in the System.Data.OleDb namespace to read a MDB file into a datagrid. You instantiate a OleDbConnection object using a connection string to your MDB file. You then instantiate a OleDbDataAdapter that uses this connection object and a SQL query. Next you create a DataSet object, use the OleDbDataAdapter to fill this dataset, and finally attached this dataset to your datagrid. Here is the code that does this.
 
     private void Form1_Load(object sender, System.EventArgs e) 
 
     { 
 
          // Set the connection and sql strings 
 
          // assumes your mdb file is in your root 
 
          string connString = @"Provider=Microsoft.JET.OLEDB.4.0;data source=C:
orthwind.mdb"; 
 
          string sqlString = "SELECT * FROM customers"; 
 

 
          // Connection object 
 
          OleDbConnection connection = new OleDbConnection(connString); 
 

 
          // Create data adapter object 
 
          OleDbDataAdapter dataAdapter = new OleDbDataAdapter(sqlString, connection); 
 

 
          // Create a dataset object and fill with data using data adapter's Fill method 
 
          DataSet dataSet = new DataSet(); 
 
          dataAdapter.Fill(dataSet, "customers"); 
 
                
 
          // Attach dataset's DefaultView to the datagrid control 
 
          dataGrid1.DataSource = dataSet.Tables["customers"].DefaultView; 
 
     }
 

 

4.10 How do I bind a listbox or a combobox to a MDB file?     

You can use the classes in the System.Data.OleDb namespace to read a MDB file into a ListBox and a ComboBox. You instantiate a OleDbConnection object using a connection string to your MDB file. You then instantiate a OleDbDataAdapter that uses this connection object and a SQL query. Next you create a DataSet object, use the OleDbDataAdapter to fill this dataset, and finally attached this dataset to your control. Here is the code that does this.
 
     private void Form1_Load(object sender, System.EventArgs e) 
 
     { 
 
          // Set the connection and sql strings 
 
               // assumes your mdb file is in your root 
 
               string connString = @"Provider=Microsoft.JET.OLEDB.4.0;data source=C:
orthwind.mdb"; 
 
               string sqlString = "SELECT * FROM customers"; 
 

 
               // Connection object 
 
               OleDbConnection connection = new OleDbConnection(connString); 
 

 
               // Create data adapter object 
 
               OleDbDataAdapter dataAdapter = new OleDbDataAdapter(sqlString, connection); 
 

 
               // Create a dataset object and fill with data using data adapter's Fill method 
 
               DataSet dataSet = new DataSet(); 
 
               dataAdapter.Fill(dataSet, "customers"); 
 
                
 
               // Attach dataset's DefaultView to the combobox 
 
               listBox1.DataSource = dataSet.Tables["customers"].DefaultView; 
 
               listBox1.DisplayMember = "CustomerID"; 
 

 
               // Attach dataset's DefaultView to the combobox 
 
               comboBox1.DataSource = dataSet.Tables["customers"].DefaultView; 
 
               comboBox1.DisplayMember = "CustomerID"; 
 
     }
 

Notice that this code uses the same dataset object for both the listbox and the combobox. When done in this manner, the two controls are linked so that the selection in one control will be the selection in the other control. If you edit an entry in the combobox, the same entry is the listbox is changed. To avoid this linkage, just have a second dataset object for your second control.
 

4.11 In my databound ComboBox, how do I set the SelectedItem property?     

Use the FindStringExact method. For example, if you have set the ComboBox's ValueMember property to "OrderID", then you could call 
 
comboBox1.SelectedIndex = comboBox1.FindStringExact(stringOrderID);
 

where stringOrderID is the "orderID" of the row to be selected. 
 

4.12 Are server side cursors supported in .NET?     

No. Nicholas Paldino gives the following response in a position to the microsoft.public.dotnet.framework.odbcnet newsgroup.

There are no updateable cursors ANYWHERE in .NET for that matter. The way .NET handles data is you push it into a dataset. The dataset keeps track of the changes that are made, and then you pass the data set back to a data adapter, which will fire off the appropriate insert, update, and delete statements in order to update the underlying data source.

All of the data access in .NET is based on a disconnected data model. 
 

4.13 I am populating a ListBox by binding it to an ArrayList. The initial display is OK, but later changes to my ArrayList are not shown in my ListBox. How can I get the changes to show properly?     

In an ArrayList, the 'plumbing' is not available to support two-way binding as with a dataset. So, you have to handle the synchronization yourself. One way to do this is to set the listBox1.DataSource to null and then reset it to your ArrayList. Another way is to use the CurrencyManager as shown in the code below. 
 
     private System.Windows.Forms.ListBox listBox1; 
 
     private System.Windows.Forms.Button button1; 
 
     private ArrayList myArrayList; 
 

 
     public Form1() 
 
     { 
 
          // 
 
          // Required for Windows Form Designer support 
 
          // 
 
          InitializeComponent(); 
 

 
          myArrayList = new ArrayList(); 
 

 
          myArrayList.Add("orange"); 
 
          myArrayList.Add("green"); 
 
          myArrayList.Add("blue"); 
 
          myArrayList.Add("red"); 
 
           
 
          listBox1.DataSource = myArrayList; 
 
     } 
 
     ...... 
 
     //change the arraylist 
 
     private void button1_Click(object sender, System.EventArgs e) 
 
     { 
 
          myArrayList[1] = "pink"; 
 
          myArrayList.Add("lavendar"); 
 

 
          //use currency manger to sync up the listbox 
 
          BindingManagerBase bm = this.listBox1.BindingContext[myArrayList]; 
 
          CurrencyManager cm = (CurrencyManager) bm; 
 
          if (cm != null) 
 
               cm.Refresh(); 
 
                
 
          //Or, you can just reset the datasource 
 
          //listBox1.DataSource = null; 
 
          //listBox1.DataSource = myArrayList; 
 
     }
 

 

4.14 My SQL server runs on a non-default port. How can I specify this port in my connection string?     

The data source component of your connection string should contain the port right after the IP address (or name). It should be separated from the IP by a comma.

 

 
data source=192.168.123.1, port number; 
 

 

Take a look at this web site for great information on several connection strings. 

http://www.connectionstrings.com/ 

 

4.15 What is a DataSet?     

Think of a DataSet object as a local in memory copy of database tables. With the client server model, client applications held onto a connection and updated and added records at will. With ADO.NET the dataset presents a disconnected model. Data as well as data changes are contained in the dataset with no physical connection to the datasource. 

Changes can be reconciled against any datasource at any time. 

A Dataset is not limited to database tables. It can work with XML or for that matter any other data. 

 

4.16 How do I add updating support to a dataset?     

To be able to write changes back to the datasource, the data adapter object that populates your dataset should have commands set for updating, deleting etc. Fortunately, there is a class called SqlCommandBuilder that generates these commands from our Select command. All we have to do is instantiate this class passing it in the data adapter that we use.

Enclosed is a complete sample: simpledata4.zip 
 

 
// Command builder will generate the command required to update the 
 
// datasource from your select statement 
 
SqlCommandBuilder commandBuilder = new SqlCommandBuilder(this.dataAdapter); 
 

 

After this is done whenever you wish to write changes back to the data source simply call Update on the data adapter as shown below. 
 

 
if(this.dataSet != null && this.dataSet.HasChanges()) 
 
this.dataAdapter.Update(this.dataSet, "Customers"); 
 

 

 

4.17 How can I import a CSV file into a DataTable?     

Here is a solution suggested by Elan Zhou (MS) on the microsoft.public.dotnet.languages.vb newsgroup.

You can also use the following code:
1. Put a DataGrid on the form.
2. Try the following sample code: (Suppose the csv is c:	est.csv.) 
 

 
Imports System.Data 
 
Imports System.Data.OleDb 
 

 

 
Public Class Form1 
 
     Inherits System.Windows.Forms.Form 
 
     Dim objDataset1 As DataSet() 
 

 
     Private Sub Form1_Load(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles MyBase.Load 
 

 
          Dim sConnectionString As String = "Provider=Microsoft.Jet.OLEDB.4.0;Data Source=c:\;Extended Properties=Text;" 
 
          Dim objConn As New OleDbConnection(sConnectionString) 
 
          objConn.Open() 
 

 
          Dim objCmdSelect As New OleDbCommand("SELECT * FROM test.csv", objConn) 
 
          Dim objAdapter1 As New OleDbDataAdapter() 
 
          objAdapter1.SelectCommand = objCmdSelect 
 

 
          Dim objDataset1 As New DataSet() 
 
          objAdapter1.Fill(objDataset1, "Test") 
 
          DataGrid1.DataSource = objDataset1.Tables(0).DefaultView 
 
          objConn.Close() 
 
     End Sub 
 
End Class 
 

 

 

4.18 How can I prevent a ComboBox and DataGrid bound to the same DataTable from sharing the same current position?     

If you have two controls bound to the same datasource, and you do not want them to share the same position, then you must make sure that the BindingContext member of one control differs from the BindingContext member of the other control. If they have the same BindingContext, they will share the same position in the datasource.

If you add a ComboBox and a DataGrid to a form, the default behavior is for the BindingContext member of each of the two controls to be set to the Form's BindingContext. Thus, the default behavior is for the DataGrid and ComboBox to share the same BindingContext, and hence the selection in the ComboBox is synchronized with the current row of the DataGrid. If you do not want this behavior, you should create a new BindingContext member for at least one of the controls. 
 
[C#] 
 
private void Form1_Load(object sender, System.EventArgs e) 
 
{ 
 
     this.myDataTable = GetATable(); //get a datatable somehow... 
 

 
     this.dataGrid1.DataSource = myDataTable; 
 

 
     //set a new binding context for the combobox 
 
     this.comboBox1.BindingContext = new BindingContext(); 
 
     this.comboBox1.DataSource = myDataTable; 
 
     this.comboBox1.DisplayMember = "Col1"; 
 
     this.comboBox1.ValueMember = "Col1"; 
 
} 
 

 
[VB.NET] 
 
Private Sub Form1_Load(ByVal sender as Object, ByVal e as System.EventArgs) 
 

 
     Me.myDataTable = GetATable() 'get a datatable somehow... 
 

 
     Me.dataGrid1.DataSource = myDataTable 
 

 
     'set a new binding context for the combobox 
 
     Me.comboBox1.BindingContext = New BindingContext() 
 
     Me.comboBox1.DataSource = myDataTable 
 
     Me.comboBox1.DisplayMember = "Col1" 
 
     Me.comboBox1.ValueMember = "Col1" 
 
End Sub 
 

 

 

4.19 I get a 'This would cause two bindings in the collection to bind to the same property' error message. What might cause this?     

As the message suggests, the code is calling Control.DataBindings.Add twice with what amounts to the same parameters.

One way this might happen is if you call the same code more than once in your program to reload your datasource for some reason, and in this code, you have lines such as: 
 
Me.TextBox1.DataBindings.Add("Text", myDataTable, "Col1Name") 
 
Me.TextBox2.DataBindings.Add("Text", myDataTable, "Col2Name") 
 
Me.TextBox3.DataBindings.Add("Text", myDataTable, "Col3Name")
 

On the second call, this would attempt to add a duplicate binding to the DataBindings collection. One solution is to Clear the DataBindings collection before you add your new binding. 
 
Me.TextBox1.DataBindings.Clear(); 
 
Me.TextBox1.DataBindings.Add("Text", myDataTable, "Col1Name") 
 
Me.TextBox2.DataBindings.Clear(); 
 
Me.TextBox2.DataBindings.Add("Text", myDataTable, "Col2Name") 
 
Me.TextBox3.DataBindings.Clear(); 
 
Me.TextBox3.DataBindings.Add("Text", myDataTable, "Col3Name")
 

 

4.20 How do I bind a TextBox to a nested relation?     

Say you have a Parent table related to a Child table related to a GrandChildTable, and you want to bind a TextBox to a column in the GrandChild table.

To do this you have to have nested relations defined, and you use this nesting to create the DataMember parameter for the the DataBinding that you add to the TextBox. Below are some code snippets. They show the DataMember as "ParentToChild.ChildToGrandChild.Name" which creates a path from the parent table down to the field in the nested relation by stringing the relation names together separated with a period. You can also download both C# and VB projects. 
 

 
Dim dSet As New DataSet() 
 

 
'get the tables 
 
Dim parentTable As DataTable = GetParentTable() 
 
Dim childTable As DataTable = GetChildTable() 
 
Dim grandChildTable As DataTable = GetGrandChildTable() 
 
dSet.Tables.AddRange(New DataTable() {parentTable, childTable, grandChildTable}) 
 

 
'setup the relations 
 
Dim parentColumn As DataColumn = parentTable.Columns("parentID") 
 
Dim childColumn As DataColumn = childTable.Columns("ParentID") 
 
dSet.Relations.Add("ParentToChild", parentColumn, childColumn) 
 

 
parentColumn = childTable.Columns("childID") 
 
childColumn = grandChildTable.Columns("ChildID") 
 
dSet.Relations.Add("ChildToGrandChild", parentColumn, childColumn) 
 

 
Me.TextBox1.DataBindings.Add("Text", parentTable, "ParentToChild.ChildToGrandChild.Name") 
 

 

 

4.21 How do I call a SQL stored procedure?     

You can call stored procedures in basically the same manner as executing other SQL commands.

When creating the SqlCommand, set the query string to be the name of the stored procedure, and then set the CommandType to be CommandType.StoredProcedure. 
 

 
if(sqlConn.State == ConnectionState.Closed)sqlConn.Open(); 
 

 
SqlCommand cmd = new SqlCommand("sp_my_stored_procedure",sqlConn); 
 
cmd.CommandTimeout = 180; 
 
cmd.CommandType = CommandType.StoredProcedure; 
 

 

After you setup the command type, you need to pass in any parameters required for the stored procedure. Here is an example of one input and one output parameter. 
 

 
SqlParameter parm; 
 

 
parm = cmd.Parameters.Add(new SqlParameter("@oid", SqlDbType.VarChar,50)); 
 
parm.Direction = ParameterDirection.Input; 
 
cmd.Parameters["@oid"].Value = OrderID; 
 

 
parm = cmd.Parameters.Add(new SqlParameter("@custName", SqlDbType.VarChar,50)); 
 
parm.Direction = ParameterDirection.Output; 
 

 

If the stored procedure is returning a selection query at the end, you can fill your DataSet and retrieve any tables. 
 

 
SqlDataAdapter tempDA = new SqlDataAdapter(); 
 
tempDA.TableMappings.Add("your mapping","your mapping"); 
 
tempDA.SelectCommand = cmd; 
 
DataSet dataSet1 = new DataSet(); 
 
tempDA.Fill(dataSet1); 
 
DataTable resultTable = dataSet1.Tables[0]; 
 

 

Or, if no tables are being returned, you can execute the command as a non-query 
 

 
cmd.ExecuteNonQuery(); 
 

 

 

4.22 I programatically change a bound TextBox value, but the value does not get pushed back into the bound datasource. How can I make sure the DataSource is updated?     

You can call the EndCurrentEdit method on the bindingmanager for the TextBox.

 
[C#] 
 
     this.textBox1.Text = "XXXX"; //set the value 
 
     this.textBox1.DataBindings["Text"].BindingManagerBase.EndCurrentEdit(); //end the edit 
 
 
 
Tu colle ca sur chaque TextBox.leave(...) et tu es censé etre sur que  cela est bien insérer dans ta table

http://www.syncfusion.com/FAQ/WinForms/FAQ_c43c.asp#q1017q

taoetc · Answer

Oula désolé , il m'a collé tout le html alors que j'ai fait un copier que de la fin , lit les deux trois premiere ligne du mail et les dix dernière du mail précédent

Arthenius · Answer

ok je jette un ooeuil...
g parler trop vite...
ca fonctionne a partir du moment ou j'utilise ma souris pour valider....
mais j'ai des touches de raccourci (CTRL+S) pour sauvegarder...
et la forcement ca marche pas....

:o(((((

mais bon je dois pouvoir trouver un truc pour forcer le beginedit et le endedit...
en placant ton code dans un autre evenement par exemple...

je cherche ... :o)))

Arthenius

"Ce qui ne me tue pas, me rend plus fort..."

Arthenius · Answer

CA Y EST !!!!

:o)))

alors pour le binding d'un dataset sur des textbox et combo voila le code a mettre : 


txt_code.DataBindings.Clear();
txt_code.DataBindings.Add(new Binding("Text", ds.Tables["T_USER"], "USRCOD"));
txt_nom.DataBindings.Clear();
txt_nom.DataBindings.Add(new Binding("Text", ds.Tables["T_USER"], "USRNOM1"));
txt_prenom.DataBindings.Clear();
txt_prenom.DataBindings.Add(new Binding("Text", ds.Tables["T_USER"], "USRNOM2"));
cbo_groupe.DataBindings.Clear();
cbo_groupe.DataBindings.Add(new Binding("SelectedValue", ds.Tables["T_USER"], "GRPNUM"));


et pour forcer la validation de la saisie (juste avant la validation) : 


this.txt_code.DataBindings["Text"].BindingManagerBase.EndCurrentEdit(); 
this.txt_nom.DataBindings["Text"].BindingManagerBase.EndCurrentEdit(); 
this.txt_prenom.DataBindings["Text"].BindingManagerBase.EndCurrentEdit();
this.cbo_groupe.DataBindings["SelectedValue"].BindingManagerBase.EndCurrentEdit();


et la tout de suite c un peu plus propre... :o)))

merci taoetc pour le lien que j'avais deja et que j'ai oublie perdu qu'il etait dans ma liste de favoris :o)))

Arthenius

"Ce qui ne me tue pas, me rend plus fort..."

cs_aeled · Answer

Cool, c'est pile poil ce que je cherchais. Merci bien :)



Juste une question : pourquoi faire :



txt_code.DataBindings.Add(new Binding("Text", ds.Tables["T_USER"], "USRCOD"));

et non pas :



txt_code.DataBindings.Add("Text", ds.Tables["T_USER"], "USRCOD");




Qui marche aussi si je ne m'abuse.


David

-----
Un jour, je saurai !

Arthenius · Answer

c pareil...
tu as le choix....


Arthenius
http://blogs.developpeur.org/Arthenius/

"Ce qui ne me tue pas, me rend plus fort..."

Winform : Binding et Rowstate de Dataset

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