modify datarow value for a specific gridview column - asp.net

Question

how would i change the value IBM to something arbitrary like Cisco in one of the gridview events listed?
there can be varying columns in the dynamic gridview so would be nice to address the column by name.
namespace WebApplication1
{
public partial class _Default : System.Web.UI.Page
{
protected void Page_Load(object sender, EventArgs e)
{
DataTable dt = new DataTable("TestTable");
dt.Columns.AddRange(new DataColumn[] { new DataColumn("id"), new DataColumn("customername") });
DataRow dr = dt.NewRow();
dr[0] = "1";
dr[1] = "Microsoft";
dt.Rows.Add(dr);
DataRow dr2 = dt.NewRow();
dr2[0] = "2";
dr2[1] = "IBM";
dt.Rows.Add(dr2);
GridView1.DataSource = dt;
GridView1.DataBind();
}
protected void GridView1_DataBinding(object sender, EventArgs e)
{
}
protected void GridView1_DataBound(object sender, EventArgs e)
{
}
protected void GridView1_RowDataBound(object sender, GridViewRowEventArgs e)
{
}
protected void GridView1_RowCreated(object sender, GridViewRowEventArgs e)
{
}
}
}

Answer 1

This won't work when AutogenerateColumns is set to true(default). You need to add the columns programmatically or declaratively(in aspx markup). Then you can use a TemplateField with a Control like Label that you can reference in codebehind:
For example:
<asp:GridView ID="GridView1" AutoGenerateColumns="false" OnRowDataBound="GridView1_RowDataBound" runat="server">
<Columns>
<asp:TemplateField HeaderText="Customer">
<ItemTemplate>
<asp:Label ID="LblCustomer" runat="server"></asp:Label>
</ItemTemplate>
</asp:TemplateField>
</Columns>
</asp:GridView>
RowDataBound is perfect(for almost everything):
protected void GridView1_RowDataBound(object sender, GridViewRowEventArgs e)
{
if(e.Row.RowType == DataControlRowType.DataRow) {
var row = ((DataRowView)e.Row.DataItem).Row;
var lblCustomer = (Label)e.Row.FindControl("LblCustomer");
var customerName = row.Field<String>( "customername" );
if(customerName == "Microsoft") {
customerName = "Cisco";
}
lblCustomer.Text = customerName;
}
}
Edit: Ok, never needed to do such. But actually you can change the Microsoft values to Cisco even with AutoGenerateColumns set to true.
DataBinding event is triggered before the GridView is databound. If you change the datasource before it's bound to grid, you'll be able to modify it:
protected void GridView1_DataBinding(object sender, EventArgs e)
{
var tbl = (DataTable)((GridView)sender).DataSource;
var msRows = tbl.AsEnumerable()
.Where(r => r.Field<String>("customername") == "Microsoft")
.Select(r => r);
foreach(DataRow msRow in msRows) {
msRow[ "customername" ] = "Cisco";
}
}
Note: of course you can also use a simple loop instead of LINQ