Newbie Help

  • Thread starter Thread starter Guest
  • Start date Start date
G

Guest

How do I perform an undo in a datagrid? Below is the code that I am trying
to work with and it is not working. School11 is my dataset, Student is a
table in an access db. I am using a Windows Form with a datagrid1. Can
someone please give me a hand?

Private Sub btnUndo_Click(ByVal sender As System.Object, ByVal e As
System.EventArgs) Handles btnUndo.Click

School11.Tables("Student").RejectChanges()
DataGrid1.Refresh()

End Sub()
 
You undo the datagrid exactly be calling the RejectChanges method
see this example (using an access db).

using System;
using System.Drawing;
using System.Collections;
using System.ComponentModel;
using System.Windows.Forms;
using System.Data;

namespace DatagridUndoExample
{
/// <summary>
/// Summary description for Form1.
/// </summary>
public class Form1 : System.Windows.Forms.Form
{
private System.Windows.Forms.DataGrid dataGrid1;
private System.Windows.Forms.Button buttonUndo;
private System.Data.OleDb.OleDbCommand oleDbSelectCommand1;
private System.Data.OleDb.OleDbCommand oleDbInsertCommand1;
private System.Data.OleDb.OleDbCommand oleDbUpdateCommand1;
private System.Data.OleDb.OleDbCommand oleDbDeleteCommand1;
private System.Data.OleDb.OleDbConnection oleDbConnection1;
private System.Data.OleDb.OleDbDataAdapter oleDbDataAdapter1;
private DatagridUndoExample.DataSet1 dataSet11;
private System.Windows.Forms.Button buttonSave;
/// <summary>
/// Required designer variable.
/// </summary>
private System.ComponentModel.Container components = null;

public Form1()
{
//
// Required for Windows Form Designer support
//
InitializeComponent();

//
// TODO: Add any constructor code after InitializeComponent call
//
}

/// <summary>
/// Clean up any resources being used.
/// </summary>
protected override void Dispose( bool disposing )
{
if( disposing )
{
if (components != null)
{
components.Dispose();
}
}
base.Dispose( disposing );
}

#region Windows Form Designer generated code
/// <summary>
/// Required method for Designer support - do not modify
/// the contents of this method with the code editor.
/// </summary>
private void InitializeComponent()
{
this.dataGrid1 = new System.Windows.Forms.DataGrid();
this.buttonUndo = new System.Windows.Forms.Button();
this.oleDbSelectCommand1 = new System.Data.OleDb.OleDbCommand();
this.oleDbInsertCommand1 = new System.Data.OleDb.OleDbCommand();
this.oleDbUpdateCommand1 = new System.Data.OleDb.OleDbCommand();
this.oleDbDeleteCommand1 = new System.Data.OleDb.OleDbCommand();
this.oleDbConnection1 = new System.Data.OleDb.OleDbConnection();
this.oleDbDataAdapter1 = new System.Data.OleDb.OleDbDataAdapter();
this.dataSet11 = new DatagridUndoExample.DataSet1();
this.buttonSave = new System.Windows.Forms.Button();
((System.ComponentModel.ISupportInitialize)(this.dataGrid1)).BeginInit();
((System.ComponentModel.ISupportInitialize)(this.dataSet11)).BeginInit();
this.SuspendLayout();
//
// dataGrid1
//
this.dataGrid1.DataMember = "";
this.dataGrid1.HeaderForeColor = System.Drawing.SystemColors.ControlText;
this.dataGrid1.Location = new System.Drawing.Point(16, 24);
this.dataGrid1.Name = "dataGrid1";
this.dataGrid1.Size = new System.Drawing.Size(160, 208);
this.dataGrid1.TabIndex = 0;
this.dataGrid1.Navigate += new
System.Windows.Forms.NavigateEventHandler(this.dataGrid1_Navigate);
//
// buttonUndo
//
this.buttonUndo.Location = new System.Drawing.Point(192, 64);
this.buttonUndo.Name = "buttonUndo";
this.buttonUndo.TabIndex = 1;
this.buttonUndo.Text = "Undo";
this.buttonUndo.Click += new System.EventHandler(this.buttonUndo_Click);
//
// oleDbSelectCommand1
//
this.oleDbSelectCommand1.CommandText = "SELECT Col1, ID FROM Table1";
this.oleDbSelectCommand1.Connection = this.oleDbConnection1;
//
// oleDbInsertCommand1
//
this.oleDbInsertCommand1.CommandText = "INSERT INTO Table1(Col1) VALUES
(?)";
this.oleDbInsertCommand1.Connection = this.oleDbConnection1;
this.oleDbInsertCommand1.Parameters.Add(new
System.Data.OleDb.OleDbParameter("Col1",
System.Data.OleDb.OleDbType.VarWChar, 50, "Col1"));
//
// oleDbUpdateCommand1
//
this.oleDbUpdateCommand1.CommandText = "UPDATE Table1 SET Col1 = ? WHERE
(ID = ?) AND (Col1 = ? OR ? IS NULL AND Col1 IS " +
"NULL)";
this.oleDbUpdateCommand1.Connection = this.oleDbConnection1;
this.oleDbUpdateCommand1.Parameters.Add(new
System.Data.OleDb.OleDbParameter("Col1",
System.Data.OleDb.OleDbType.VarWChar, 50, "Col1"));
this.oleDbUpdateCommand1.Parameters.Add(new
System.Data.OleDb.OleDbParameter("Original_ID",
System.Data.OleDb.OleDbType.Integer, 0,
System.Data.ParameterDirection.Input, false, ((System.Byte)(0)),
((System.Byte)(0)), "ID", System.Data.DataRowVersion.Original, null));
this.oleDbUpdateCommand1.Parameters.Add(new
System.Data.OleDb.OleDbParameter("Original_Col1",
System.Data.OleDb.OleDbType.VarWChar, 50,
System.Data.ParameterDirection.Input, false, ((System.Byte)(0)),
((System.Byte)(0)), "Col1", System.Data.DataRowVersion.Original, null));
this.oleDbUpdateCommand1.Parameters.Add(new
System.Data.OleDb.OleDbParameter("Original_Col11",
System.Data.OleDb.OleDbType.VarWChar, 50,
System.Data.ParameterDirection.Input, false, ((System.Byte)(0)),
((System.Byte)(0)), "Col1", System.Data.DataRowVersion.Original, null));
//
// oleDbDeleteCommand1
//
this.oleDbDeleteCommand1.CommandText = "DELETE FROM Table1 WHERE (ID = ?)
AND (Col1 = ? OR ? IS NULL AND Col1 IS NULL)";
this.oleDbDeleteCommand1.Connection = this.oleDbConnection1;
this.oleDbDeleteCommand1.Parameters.Add(new
System.Data.OleDb.OleDbParameter("Original_ID",
System.Data.OleDb.OleDbType.Integer, 0,
System.Data.ParameterDirection.Input, false, ((System.Byte)(0)),
((System.Byte)(0)), "ID", System.Data.DataRowVersion.Original, null));
this.oleDbDeleteCommand1.Parameters.Add(new
System.Data.OleDb.OleDbParameter("Original_Col1",
System.Data.OleDb.OleDbType.VarWChar, 50,
System.Data.ParameterDirection.Input, false, ((System.Byte)(0)),
((System.Byte)(0)), "Col1", System.Data.DataRowVersion.Original, null));
this.oleDbDeleteCommand1.Parameters.Add(new
System.Data.OleDb.OleDbParameter("Original_Col11",
System.Data.OleDb.OleDbType.VarWChar, 50,
System.Data.ParameterDirection.Input, false, ((System.Byte)(0)),
((System.Byte)(0)), "Col1", System.Data.DataRowVersion.Original, null));
//
// oleDbConnection1
//
this.oleDbConnection1.ConnectionString = @"Jet OLEDB:Global Partial Bulk
Ops=2;Jet OLEDB:Registry Path=;Jet OLEDB:Database Locking Mode=1;Jet
OLEDB:Database Password=;Data Source=""D:\DemoDb.mdb"";Password=;Jet
OLEDB:Engine Type=5;Jet OLEDB:Global Bulk
Transactions=1;Provider=""Microsoft.Jet.OLEDB.4.0"";Jet OLEDB:System
database=;Jet OLEDB:SFP=False;Extended Properties=;Mode=Share Deny None;Jet
OLEDB:New Database Password=;Jet OLEDB:Create System Database=False;Jet
OLEDB:Don't Copy Locale on Compact=False;Jet OLEDB:Compact Without Replica
Repair=False;User ID=Admin;Jet OLEDB:Encrypt Database=False";
//
// oleDbDataAdapter1
//
this.oleDbDataAdapter1.DeleteCommand = this.oleDbDeleteCommand1;
this.oleDbDataAdapter1.InsertCommand = this.oleDbInsertCommand1;
this.oleDbDataAdapter1.SelectCommand = this.oleDbSelectCommand1;
this.oleDbDataAdapter1.TableMappings.AddRange(new
System.Data.Common.DataTableMapping[] {
new System.Data.Common.DataTableMapping("Table",
"Table1", new System.Data.Common.DataColumnMapping[] {
new
System.Data.Common.DataColumnMapping("Col1", "Col1"),
new
System.Data.Common.DataColumnMapping("ID", "ID")})});
this.oleDbDataAdapter1.UpdateCommand = this.oleDbUpdateCommand1;
//
// dataSet11
//
this.dataSet11.DataSetName = "DataSet1";
this.dataSet11.Locale = new System.Globalization.CultureInfo("en-GB");
//
// buttonSave
//
this.buttonSave.Location = new System.Drawing.Point(192, 24);
this.buttonSave.Name = "buttonSave";
this.buttonSave.TabIndex = 3;
this.buttonSave.Text = "Save";
this.buttonSave.Click += new System.EventHandler(this.buttonSave_Click);
//
// Form1
//
this.AutoScaleBaseSize = new System.Drawing.Size(5, 13);
this.ClientSize = new System.Drawing.Size(292, 266);
this.Controls.Add(this.buttonSave);
this.Controls.Add(this.buttonUndo);
this.Controls.Add(this.dataGrid1);
this.Name = "Form1";
this.Text = "Form1";
this.Load += new System.EventHandler(this.Form1_Load);
((System.ComponentModel.ISupportInitialize)(this.dataGrid1)).EndInit();
((System.ComponentModel.ISupportInitialize)(this.dataSet11)).EndInit();
this.ResumeLayout(false);

}
#endregion

/// <summary>
/// The main entry point for the application.
/// </summary>
[STAThread]
static void Main()
{
Application.Run(new Form1());
}

private void Form1_Load(object sender, System.EventArgs e)
{
this.oleDbDataAdapter1.Fill(this.dataSet11);
this.dataGrid1.DataSource = this.dataSet11.Table1;
}

private void buttonUndo_Click(object sender, System.EventArgs e)
{
this.dataSet11.Table1.RejectChanges();
}



private void dataGrid1_Navigate(object sender,
System.Windows.Forms.NavigateEventArgs ne)
{

}

private void buttonSave_Click(object sender, System.EventArgs e)
{
this.oleDbDataAdapter1.Update(this.dataSet11);
}
}
}
 
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