Help on getting the value of selected row from GridView

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C#

ASP.NET

Hi all,

Kindly bear with my poor programming as I am new to .Net world.

Following is a aspx code for GridView which displays results of search done in the database by user.

<div>
    <asp:GridView ID="gvwKeyList" runat="server" AutoGenerateColumns="False" EmptyDataText="No data available."
        onrowcommand="GridView_RowCommand"
        CssClass="table table-striped table-condensed" BorderStyle="None" AlternatingRowStyle-BackColor="#C0DC3B">
        <Columns>
            <asp:TemplateField>
                <ItemTemplate>
                    <asp:Button ID="b1" runat="server" Text="Attach?" CommandName="Select" class="btn btn-primary" />
                </ItemTemplate>
            </asp:TemplateField>
            <asp:BoundField DataField="key_id" HeaderText="Key Id" />
            <asp:BoundField DataField="key_no" HeaderText="Key No" />
            <asp:BoundField DataField="hook" HeaderText="Hook" />
            <asp:BoundField DataField="access_description" HeaderText="Accessible?" />
            <asp:BoundField DataField="key_type_description" HeaderText="Key Type" />
            <asp:BoundField DataField="key_location" HeaderText="Key Location" />
        </Columns>
        <SelectedRowStyle BackColor="LightCyan" ForeColor="DarkBlue" Font-Bold="true" />
    </asp:GridView>

This is working fine and I can easily display it. Here is a code for it.

protected void search_keys(object sender, EventArgs e)
{
    string key = txt_key_no.Text;
    string hook = txt_hook.Text;

    List<Key> lstKey = new List<Key>();

    key_dal objDAL = new key_dal();
    lstKey = objDAL.GetKeyListByKeyHook(key, hook);

    gvwKeyList.DataSource = lstKey;
    gvwKeyList.GridLines = GridLines.None;

    gvwKeyList.DataBind();
}

My problem starts when I want to get the value of "Key_id" when user clicks on "Attach?" button. No matter what method I have tried I am always getting an error. I cannot get the RowIndex. Here is the code for "GridView_RowCommand" method

protected void GridView_RowCommand(Object sender, GridViewCommandEventArgs e)
{
    if (e.CommandName == "Select")
    {
        // Convert the row index stored in the CommandArgument
        // property to an Integer.
        int index = Convert.ToInt32(e.CommandArgument);

        // Get the last name of the selected author from the appropriate
        // cell in the GridView control.
        GridViewRow selectedRow = gvwKeyList.Rows[index];
        TableCell contactName = selectedRow.Cells[1];
        string contact = contactName.Text;

        // Display the selected text.
        Message.Text = "You selected " + contact + ".";
    }

}

Can somebody please please guide me my mistake. I don't mind if I have to abandon this way and take up something new and better if available.

Many thanks in advance

Sorry. Somebody pointed out correctly that what do I mean by "I am always getting an error". It was my last 4 hours of frustration which prevented me from assuming things. These are the
various things I tried but always got a null Exception error.

//int rowindex = gvwKeyList.SelectedRow.RowIndex;
    //string stVal = gvwKeyList.Rows[rowindex].Cells[1].ToString();

OR
    //int selectedrowindex = gvwKeyList.SelectedRow.RowIndex;
    //GridViewRow selectedRow = gvwKeyList.Rows[selectedrowindex];
    //string stVal = Convert.ToString(selectedRow.Cells[1].ToString());
OR
    //GridViewRow row = gvwKeyList.SelectedRow;

    //GridViewRow clik = ((Button)sender).NamingContainer as GridViewRow;
    //string stVal = clik.FindControl("key_id").ToString();
OR
    // Determine the index of the selected row.
    //int index = gvwKeyList.SelectedIndex;
    //int selected_key_id = Convert.ToInt32(gvwKeyList.DataKeys[index].Value);
    //int selected_key_id = Convert.ToInt16(gvwKeyList.SelectedRow.Cells[1].Text);

Message.Text = "The primary key value of the selected row is " + stVal + ".";

I finally abandoned them and went for the "protected void GridView_RowCommand" method which gave me a "Input string was not in a correct format" error. All I want is a value from the row where I click the button