زر الحذف لا يعمل

Dim con As New SqlClient.SqlConnection("data source=.; initial catalog= library;integrated security=true")
	Dim ds As New DataSet
	Dim da As New SqlClient.SqlDataAdapter

هذا كود فتح الاتصال في المنطقة العامة

'''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''

da.SelectCommand = New SqlClient.SqlCommand
		da.SelectCommand.Connection = con
		da.SelectCommand.CommandText = "select * from br"
		da.Fill(ds, "br")
		DataGrid1.DataSource = ds.Tables("br")

هذا الكود في منطقة load form

''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''

Dim i As Integer
		Dim c As New SqlClient.SqlCommandBuilder(da)
		i = DataGrid1.CurrentRowIndex
		ds.Tables("br").Rows(i).Delete()
		da.Update(ds.Tables("br"))
		MsgBox("delet is done")

هذا كود الحذف

'''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''

لما اضغط زر الحذف تطلع هذة الرسالة

An unhandled exception of type 'System.InvalidOperationException' occurred in system.data.dll

Additional information: Dynamic SQL generation for the DeleteCommand is not supported against a SelectCommand that does not return any key column information.

مع ان استعمل هذة الطريقة على فورم ثاني شغالة

وشكرا