Unable to delete from database

Question

Unable to delete data from database in vb.net using SQL Server.

Here is my code for deletion, can you tell me where I have gone wrong?

Name of the table is OneToOne:

 Private Sub Button2_Click(sender As Object, e As EventArgs) Handles Button2.Click
    cn.Open()
    With cmd
        .Connection = cn
        .CommandText = " DELETE * FROM OneToOne WHERE SrNo = " & DataGridView1.SelectedRows(0).Cells(0).Value
        i = cmd.ExecuteNonQuery
    End With
    If (i > 0) Then
        MsgBox("Conversation Deleted")
    End If
    cn.Close()
    showdata()
End Sub

Answer 1

To delete all rows at once, you can iterate through the selected rows and build a comma-separated string of the Cell(0) values.

Then instead of using WHERE srNo = , use WHERE srNo IN ({your string})

At least, this is the way to do it following your current approach. A better way would be to pass a table-valued parameter to a stored procedure, but that's a broad subject that you would need to research.

And, as with most programming questions, there are multiple other ways this can be done.

Answer 2

on_button_click

s = "DELETE FROM OneToOne WHERE SrNo IN(val1,val2.....valn)" 
        cn.Open()
        cmd = New SqlCommand(s, cn)
        i = cmd.ExecuteNonQuery()
       If i > 0 Then
            MsgBox("yup")
        End If
        cn.Close()

val1,val2.. are your SrNo values. It's on you how you retrieve/provide SrNo values