Binding dropdown list in a gridview edit item template

Question

i can bind the dropdownlist in the edit item template. The drop down list is having null values.

protected void grdDevelopment_RowDataBound(object sender, GridViewRowEventArgs e) 
{   
  DropDownList drpBuildServers = new DropDownList();

  if (grdDevelopment.EditIndex == e.Row.RowIndex)    
  {        
      drpBuildServers = (DropDownList)e.Row.Cells[0].FindControl("ddlBuildServers");    
  }
}

also getting an error

Failed to load viewstate. The control tree into which viewstate is being loaded must match the control tree that was used to save viewstate during the previous request. For example, when adding controls dynamically, the controls added during a post-back must match the type and position of the controls added during the initial request.

Answer 1

I had problems with find control, in the end I used a little bit of recursion to find the control:

private Control FindControlRecursive(Control root, string id) 
{ 
     if (root.ID == id)
    { 
         return root; 
    } 

    foreach (Control c in root.Controls) 
    { 
         Control t = FindControlRecursive(c, id); 
        if (t != null) 
        { 
            return t; 
        } 
    } 

     return null; 
}

Then to find your control make this call:

drpBuildServers = (DropDownList) FindControlRecursive(e.Row.Cells[0], "ddlBuildServers");

Answer 2

protected void grdDevelopment_RowDataBound(object sender, GridViewRowEventArgs e)
{
    if (e.Row.RowType == DataControlRowType.DataRow)
    {
        DropDownList drpBuildServers;

        drpBuildServers = e.Row.FindControl("ddlBuildServers") as DropDownList;

        if (drpBuildServers != null)
            // Write your code here            
    }
}