get value into query from edit mode in gridview - asp.net

Question

I have a simple gridview, 2 columns. The first column is a numeric value. The second column is based on a selected value from a drop down list. I have the drop down list working, but when I go to update the table, I get an error :
Index was out of range. Must be non-negative and less than the size of the collection.
Parameter name: index
The offending line is 55
Line 53: {
Line 54: string BU = (gvSummary.Rows[e.RowIndex].FindControl("dlBU") as DropDownList).SelectedItem.Value;
Line 55: string AnnoNum = gvSummary.DataKeys[e.RowIndex].Value.ToString();
and here is the code behind for the webform:
using System;
using System.Collections.Generic;
using System.Linq;
using System.Web;
using System.Web.UI;
using System.Web.UI.WebControls;
using System.Data;
using System.Data.SqlClient;
using System.Web.Security;
using System.Configuration;
namespace SHCAnnotation
{
public partial class WebForm2 : System.Web.UI.Page
{
protected void Page_Load(object sender, EventArgs e)
{
if (!IsPostBack)
{
this.BindData();
}
}
protected void EditSummary(object sender, GridViewEditEventArgs e)
{
gvSummary.EditIndex = e.NewEditIndex;
BindData();
}
protected void CancelEdit(object sender, GridViewCancelEditEventArgs e)
{
gvSummary.EditIndex = -1;
BindData();
}
protected void RowDataBound(object sender, GridViewRowEventArgs e)
{
if (e.Row.RowType == DataControlRowType.DataRow && gvSummary.EditIndex == e.Row.RowIndex)
{
DropDownList dlBU = (DropDownList)e.Row.FindControl("dlBU");
string query = "select distinct Unit from vw_KmartBU";
SqlCommand cmd = new SqlCommand(query);
dlBU.DataSource = GetData(cmd);
dlBU.DataTextField = "Unit";
dlBU.DataValueField = "Unit";
dlBU.DataBind();
//dlBU.Items.FindByValue((e.Row.FindControl("lblBU") as Label).Text).Selected = true;
}
}
protected void UpdateSummary(object sender, GridViewUpdateEventArgs e)
{
string BU = (gvSummary.Rows[e.RowIndex].FindControl("dlBU") as DropDownList).SelectedItem.Value;
string AnnoNum = gvSummary.DataKeys[e.RowIndex].Value.ToString();
string strConnString = ConfigurationManager.ConnectionStrings["SRM_MetricConnectionString"].ConnectionString;
using (SqlConnection con = new SqlConnection(strConnString))
{
string query = "update vw_GridviewSource set [Business Unit] = #BU where [Annotation Number] = #AnnoNum";
using (SqlCommand cmd = new SqlCommand(query))
{
cmd.Connection = con;
cmd.Parameters.AddWithValue("#BU", BU);
cmd.Parameters.AddWithValue("#AnnoNum", AnnoNum);
con.Open();
cmd.ExecuteNonQuery();
con.Close();
Response.Redirect(Request.Url.AbsoluteUri);
}
}
}
private void BindData()
{
string query = "select [Annotation Number], [Business Unit] as Unit from vw_GridviewSource";
SqlCommand cmd = new SqlCommand(query);
gvSummary.DataSource = GetData(cmd);
gvSummary.DataBind();
}
private DataTable GetData(SqlCommand cmd)
{
string strConnString = ConfigurationManager.ConnectionStrings["SRM_MetricConnectionString"].ConnectionString;
using (SqlConnection con = new SqlConnection(strConnString))
{
using (SqlDataAdapter sda = new SqlDataAdapter())
{
cmd.Connection = con;
sda.SelectCommand = cmd;
using (DataTable dt = new DataTable())
{
sda.Fill(dt);
return dt;
}
}
}
}
}
}
What I need to do is get the value in first column "Annotation Number" and use it in the where clause of my update. So I would need update vw_GridviewSource set [Business Unit] = 'Accessories' where [Annotation Number] = '123456'
Accessories would have been the selection from the drop down list and 123456 would have been in the text box when I selected that row for editing.

Answer 1

Your gridview is missing DataKeyNames. It may look like:
<asp:GridView ID="gvSummary"
runat="server"
AutoGenerateColumns="False"
DataKeyNames="AnnoNum, MyOtherKey1, MyOtherKey2"
... ... ...
DataKeyNames property is an array of strings. You can find more in MSDN