exception in find dropdown

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postgdetails.Qua = ((DropDownList)GridView1.Rows[e.RowIndex].Cells[1].Controls[0]).SelectedItem.ToString();

where postgdetails is a object of a class.
when debug this code it throw a exception in this line .exception are given below

Unable to cast object of type 'System.Web.UI.LiteralControl' to type 'System.Web.UI.WebControls.DropDownList'.

while

postgdetails.Medium = ((DropDownList)GridView1.Rows[e.RowIndex].Cells[2].Controls[0]).SelectedItem.Text.ToString();

this line is working properly in same program how is that.

plz tell me about that problem.

Posted 5-Jul-12 21:43pm

srishti_

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Sergey Alexandrovich Kryukov · Answer 1 · 2012-07-05T21:50:00

The run-time types of the cell contents are different for the different cells. One type is DropDownList or assignment-compatible with it, another type is not. When you dynamically down-cast it to an incompatible type, it throws this exception. Check up what is actually in the cell in question. As simple as that.

Generally, it can be good to check up a run-time type instead of blind-folded type casting. Something like that:

C#

DropDownList list = GridView1.Rows[e.RowIndex].Cells[1].Controls[0] as DropDownList;
if (list != null) // successful cast
   postgdetails.Qua = list.SelectedItem.ToString();
else
   MessageBox.Show("Oh no! Not again! :-)");

—SA