SqlDataSource.DeleteCommand Property
Assembly: System.Web (in system.web.dll)
Because different database products use different varieties of SQL, the syntax of the SQL string depends on the current ADO.NET provider being used, which is identified by the ProviderName property. If the SQL string is a parameterized query or command, the syntax of the parameter also depends on the ADO.NET provider being used. For example, if the provider is the System.Data.SqlClient, which is the default provider for the SqlDataSource class, the syntax of the parameter is '@parameterName'. However, if the provider is set to the System.Data.Odbc or System.Data.OleDb, the placeholder of the parameter is '?'. For more information on parameterized SQL queries and commands, see Parameters with the SqlDataSource and AccessDataSource Controls.
The DeleteCommand property can be an SQL string or the name of a stored procedure, if the database supports stored procedures.
The DeleteCommand property delegates to the DeleteCommand property of the SqlDataSourceView object that is associated with the SqlDataSource control.
 Security Note: |
|---|
| For security purposes, the DeleteCommand property is not stored in view state. Because it is possible to decode the contents of view state on the client, storing sensitive information about the database structure in view state could result in an information disclosure vulnerability. |
The following code example demonstrates how to set the DeleteCommand text to delete an order from the Northwind database Orders table. Data is retrieved from the Orders table and displayed in a GridView control. The GridView renders a Delete button automatically when the AutoGenerateDeleteButton property is set to true. Additionally, when the Delete button is clicked, the GridView control automatically populates the DeleteParameters collection and calls the Delete method. Finally, because this code example deletes data, an event handler is added to attempt to back up the database to disk before the Delete operation is performed.
<%@Page Language="VJ#" %>
<%@Import Namespace="System.Data.SqlClient" %>
<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">
<script runat="server">
private void OnRecordDeleting(Object source,
SqlDataSourceCommandEventArgs e)
{
// Because this example actually deletes data from the Northwind
// database, provide a way for users to recover any deleted records.
SqlConnection cxn = new SqlConnection(
"Data Source=localhost;Integrated Security=SSPI;"
+ "Initial Catalog=Northwind;Connect Timeout=15");
try {
cxn.Open();
SqlCommand backup = new SqlCommand();
backup.set_Connection (cxn);
backup.set_CommandText(
" USE master " + " EXEC sp_addumpdevice 'disk','Northwind_1',"
+ "'c:\\temp\\Northwind_1.dat'"
+ " BACKUP DATABASE Northwind TO Northwind_1");
backup.ExecuteNonQuery();
}
catch (SqlException se) {
// Handle an exception thrown if the device already exists.
Label1.set_Text("An error occurred while backing up your "
+ "database. Please check the SQL logs.");
}
finally {
// Always release the connection.
cxn.Dispose();
}
Label1.set_Text("A record has been deleted. To recover your data, "
+ "restore the database from the "
+ "database backup named Northwind_1.dat located on the database "
+ "server in c:\\temp.");
} //OnRecordDeleting
</script>
<html xmlns="http://www.w3.org/1999/xhtml" >
<head runat="server">
<title>ASP.NET Example</title>
</head>
<body>
<form id="form1" runat="server">
<asp:SqlDataSource
id="SqlDataSource1"
runat="server"
DataSourceMode="DataSet"
ConnectionString="Data Source=localhost;Integrated Security=SSPI;Initial Catalog=Northwind;"
SelectCommand="SELECT * FROM Orders"
DeleteCommand="DELETE FROM [Order Details] WHERE OrderID=@OrderID;DELETE FROM Orders WHERE OrderID=@OrderID;"
OnDeleting="OnRecordDeleting">
</asp:SqlDataSource>
<asp:GridView
id="GridView1"
runat="server"
AutoGenerateColumns="False"
DataKeyNames="OrderID"
AutoGenerateDeleteButton="True"
AllowPaging="True"
PageSize="20"
DataSourceID="SqlDataSource1">
<Columns>
<asp:BoundField HeaderText="Order ID" DataField="OrderID" />
<asp:BoundField HeaderText="Customer" DataField="CustomerID" />
<asp:BoundField HeaderText="Order Placed" DataField="OrderDate" />
<asp:BoundField HeaderText="Order Shipped" DataField="ShippedDate" />
</Columns>
</asp:GridView>
<asp:Label
id="Label1"
runat="server">
</asp:Label>
</form>
</body>
</html>
