Dropdroplist binding in Gridview

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Hi,
i added on dropdownlist in grid edititemtemplate, when i am binding the data in .cs file with the event rowdataboud then i got the error

System.NullReferenceException: Object reference not set to an instance of an object.

here is my sample cs code

C#

protected void gvTestType_RowDataBound(object sender, GridViewRowEventArgs e)
        {
            if (e.Row.RowType == DataControlRowType.DataRow)
            {
                DropDownList ddl = (DropDownList)e.Row.FindControl("ddlStatus");
               DataSet ds = new DataSet();
               StatusBll sBl = new StatusBll();
                ds = sBl.SelectStatusDetails();
                ddl.DataTextField = "Description";//the source of your dropdown
                ddl.DataValueField = "StatusId";
                ddl.DataSource = ds.Tables["Status"];
                ddl.DataBind();
            }
        }

Posted 14-Jun-12 3:12am

Member 9120435

Updated 14-Jun-12 3:13am

Prasad_Kulkarni

v3

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Dev-0001 14-Jun-12 9:41am

what's the error message

2 solutions

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willempipi · Answer 1 · 2012-06-14T03:27:00

Solution 1

Could be that your

sBl.SelectStatusDetails()

tries to get a variable from something that is null.

Or

ds.Tables["Status"]

doesn't exist...

Posted 14-Jun-12 3:27am

willempipi

v2

Sandeep Mewara · Answer 2 · 2012-06-14T04:45:00

Object reference not set to an instance of an object

This error happens when you try to use a property or call a method of an object that is null. More details: here[^]

A simple use of Visual studio DEBUGGER can tell you the object because of which it is happening. Just look at the stack trace and put a debugger on that line. Check the objects of that line and see if any one is null and you are trying to use that objects property. Handle the same.

Based on the code snippet shared, potential places:

C#

DropDownList ddl = (DropDownList)e.Row.FindControl("ddlStatus"); //ddlStatus was not found and explicit cast threw an error

C#

ds = sBl.SelectStatusDetails(); // ds returned is null or empty, assuming no error in method called!

C#

ddl.DataSource = ds.Tables["Status"]; // there is no table named 'Status' in the dataset ds

Check, find and fix it.