Grid view Updatearguments does Not contain New Values - asp.net

Question

public partial class Gridvw_expt2 : System.Web.UI.Page
{
SqlCommand com;
SqlDataAdapter da;
DataSet ds;
SqlConnection con=new SqlConnection(ConfigurationManager.ConnectionStrings["gj"].ConnectionString);
protected void Page_Load(object sender, EventArgs e)
{
com = new SqlCommand("Select * from tblExpt",con);
da = new SqlDataAdapter(com);
ds = new DataSet();
da.Fill(ds);
if (ds.Tables[0].Rows[0] != null)
{
GridView1.AutoGenerateEditButton = true;
GridView1.DataSource = ds;
GridView1.DataBind();
GridView1.RowUpdating += new GridViewUpdateEventHandler(GridView1_RowUpdating);
GridView1.DataKeyNames = new string[] { "id" };
GridView1.RowEditing += new GridViewEditEventHandler(GridView1_RowEditing);
}
else
Response.Write("fkj");
}
protected void GridView1_RowUpdating(object sender, GridViewUpdateEventArgs e)
{
GridViewRow row = GridView1.Rows[e.RowIndex];
int id = Convert.ToInt32(GridView1.DataKeys[e.RowIndex].Value);
string cls = ((TextBox)(row.Cells[2].Controls[0])).Text;
string nam = ((TextBox)(row.Cells[3].Controls[0])).Text;
foreach (DictionaryEntry entry in e.NewValues)
{
e.NewValues[entry.Key] = Server.HtmlEncode(entry.Value.ToString());
}
com = new SqlCommand("Update tblExpt set name='" + nam + "',class='" + cls + "' where id='" + id + "'", con);
da = new SqlDataAdapter(com);
GridView1.EditIndex = -1;
GridView1.DataSource = ds;
GridView1.DataBind();
}
protected void GridView1_RowEditing(object sender, GridViewEditEventArgs e)
{
GridView1.EditIndex = e.NewEditIndex;
GridView1.DataSource = ds;
GridView1.DataBind();
}
}
In the above code when i try to access e.new values index out of range exception is thrown.
The table being accessed contains 3 fields id, class, name
Please help to solve the problem.

Answer 1

Read this blog post I wrote on extracting data from gridview (and other data controls). Also, in .net 4.0 if you use 2 way binding (<# Bind("") #>) e.NewValues will be populated.
More info here: http://weblogs.asp.net/davidfowler/archive/2008/12/12/getting-your-data-out-of-the-data-controls.aspx

Answer 2

The exception you get is because row.Cells[0].Controls[0] is a DataControlLinkButton and not a TextBox. Since I don´t know the control layout of your grid you could search for your textbox instead.
Instead of:
int id = int.Parse(((TextBox)(row.Cells[0].Controls[0])).Text);
do something like the code below if there is only one TextBox per row:
TextBox box = (TextBox)row.Cells[0].Controls.OfType<TextBox>().First();
int id = int.Parse( box.Text );
If you have nested html and hierarchies check out this SO question for nested searching of controls