Question

I have a GridView with some data from my database.

However, when hovering the delete link, it links to the incorrect ID.

I want it to use the ID from the database.

This question is very much related to this one – but it never received an answer.

My GridView code looks like this:

<asp:GridView ID="GridView1" runat="server" OnRowDeleting="GridView1_RowDeleting1" AutoGenerateColumns="false" DataKeyNames="id">
    <Columns>
      <asp:BoundField HeaderText="Name" DataField="name" />
      <asp:BoundField HeaderText="Email" DataField="email" />
      <asp:BoundField HeaderText="Comment" DataField="comment" />
      <asp:CommandField ShowDeleteButton="True"  />
    </Columns>
</asp:GridView>

How do I make the DeleteButton link to the correct ID?

Update

Page-load code that puts the data in the datatable:

    protected void Page_Load(object sender, EventArgs e)
    {
        DataTable commentsTable = null;
        commentsTable = new DataTable("Comments");
        using (SqlDataReader reader = studentManager.getCommentsFromDB())
        {
            commentsTable.Load(reader);
            GridView1.DataSource = commentsTable;
            GridView1.DataBind();
        }
    }

getCommentsFromDB:

    public SqlDataReader getCommentsFromDB()
    {
        SqlConnection conn = dal.connectDatabase();
        conn.Open();
        cmd = new SqlCommand(@"SELECT id, name, email, comment FROM GuestBook", conn);
        rdr = cmd.ExecuteReader();
        return rdr;
    }

Answer 1

There’s a number of ways you can go about doing this. I tend to use an ASP.NET Button and set the CommandName property to "Delete".

<asp:Button ID="btnDelete" runat="server" CommandName="Delete" />

or

<asp:ImageButton ID="ibtnDelete" runat="server" ImageUrl="~/Images/Delete.gif" CommandName="Delete" />

or

<asp:CommandField ButtonType="Button" DeleteText="Delete" ShowDeleteButton="true" />

Then it’s just a matter of wiring up the event that handles OnRowDeleting.

protected void GridView1_RowDeleting1(object sender, GridViewDeleteEventArgs e) {
    // Get the id
    string id = GridView1.DataKeys[e.RowIndex].Value.ToString();

    // Create the delete query
    string sql = @"delete from GuestBook where id = @id";

    using (SqlConnection conn = dal.connectDatabase()) {

        cmd = new SqlCommand(sql, conn);
        cmd.Parameters.Add("@id", SqlDbType.Int);
        cmd.Parameters["@id"].Value = id;

        try {
            conn.Open();
            cmd.ExecuteScalar();
        }
        catch (Exception ex) {
            Console.WriteLine(ex.Message);
        }
    }

    // Refresh the GridView1
    Bind_GridView1();
}

… and the method to call each time that you want to refresh the GridView. It’s much cleaner to have your GridView binding call in it’s own method that you can call from anywhere in the page (which means that you can call it from your page load event as well).

public void Bind_GridView1() {
        DataTable commentsTable = null;
        commentsTable = new DataTable("Comments");
        using (SqlDataReader reader = studentManager.getCommentsFromDB())
        {
            commentsTable.Load(reader);
            GridView1.DataSource = commentsTable;
            GridView1.DataBind();
        }
}