filling dropdownlist doesn't work

Valerie Meunier

5y795.NET

Hi,

I try to fill via code-behind a dropdownlist located in a gridview.

But it remains empty.

Thanks for help.

protected void GridView1_RowCreated(object sender, System.Web.UI.WebControls.GridViewRowEventArgs e)
{
if ((e.Row.RowState & DataControlRowState.Edit) == DataControlRowState.Edit)
{
if (e.Row.RowType == DataControlRowType.DataRow)
{
DropDownList dd1;
ListItem z;
string m;
dd1 = (DropDownList)e.Row.FindControl("matdd");
using (SqlConnection mConnection = new SqlConnection(param.ConnectionString))
{
mConnection.Open();
sql = "select name from mat order by name";
comd = new SqlCommand(sql, mConnection);
dtreader = comd.ExecuteReader();
if (dtreader.HasRows)
{
while (dtreader.Read())
{
m = dtreader.GetString(0);
z = new ListItem(m);
dd1.Items.Add(z);
}
}
dtreader.Close();
mConnection.Close();
}
dd1.ClearSelection();
}
}
}

5 Replies

Know the answer? Post it — somebody with the same question will find it here.

Salman Beg5y ago
Accepted answer
Check this link and how he did in this link so in the same way you can do it, https://www.c-sharpcorner.com/UploadFile/009464/use-dropdownlist-in-gridview-in-Asp-Net-using-C-Sharp/
Valerie Meunier5y ago
It's solved. The problem was in the select.
Thanks
Valerie Meunier5y ago
I changed the line dd1 = (DropDownList)e.Row.FindControl("matdd");

into DropDownList dd1 = (e.Row.FindControl("matdd") as DropDownList);

and suppresses the line  DropDownList dd1;

I also changed the line  dd1.Items.Add(z); into dd1.Items.Insert(0, z);

When i run, i get

matdd' has a SelectedValue which is invalid because it does not exist in the list of items
Valerie Meunier5y ago
Hi, thanks for replying.
Yes, the select provides the data. I think the problem is finding the dropdownlist.
Here is the code in aspx:
Salman Beg5y ago
First check whether you are getting any value or not in dtreader. You can check by debugging the application. Thanks