grid view error

[nehaneha]

void GridView1_DataBound(object sender, EventArgs e)
    {
             DropDownList ddl = (DropDownList)GridView1.FindControl("drpmarks");
             DataTable dt=  ClassLibrary1.Class1.FetchMarks( 21);
      ddl.DataSource = dt;
        ddl.DataTextField = "Marks";
        ddl.DataValueField = "employeeid";
        ddl.DataBind();
 
    }
 

when i run iam getting error as null reference . can any body tell what is the problem

[kenobewan]

Your data table is prob empty, which line is the error?

[mzmishra]

Does this line returns a DataTable
ClassLibrary1.Class1.FetchMarks( 21)

[Frinavale]

void GridView1_DataBound(object sender, EventArgs e)
    {
             DropDownList ddl = (DropDownList)GridView1.FindControl("drpmarks");
             DataTable dt=  ClassLibrary1.Class1.FetchMarks( 21);
      ddl.DataSource = dt;
        ddl.DataTextField = "Marks";
        ddl.DataValueField = "employeeid";
        ddl.DataBind();
 
    }
 

when i run iam getting error as null reference . can any body tell what is the problem

Make sure that your GridView has the dropDownList "drpmarks" and also that your ClassLibrary1.Class1.FetchMarks returns an object to you that exists (is not null).

I also suggest changing your code to use a Try/Catch block so that you can set the NULL object to a reference of something when this occurs.

-Frinny

[nehaneha]

Your data table is prob empty, which line is the error?

no my datatable is not empty in dt iam getting 5 records but still iam getting an error . can't we bind directly datatable like that

[nehaneha]

Does this line returns a DataTable
ClassLibrary1.Class1.FetchMarks( 21)

yes it is returning 5 records . can't we bind datatable directly

[Shashi Sadasivan]

Could you please mention which line is the error being reported?

[nehaneha]

Could you please mention which line is the error being reported?

ddl.DataSource = mytable;

in this line iam getting an error

Object reference not set to an instance of an object.
Description: An unhandled exception occurred during the execution of the current web request. Please review the stack trace for more information about the error and where it originated in the code.

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

Source Error:


Line 87: }
Line 88:
Line 89: ddl.DataSource = mytable;
Line 90: ddl.DataTextField = "Rank";
Line 91: ddl.DataValueField = "ProposalID";

[Shashi Sadasivan]

Hi nehaneha
This only means that

DataTable dt=  ClassLibrary1.Class1.FetchMarks( 21);

is returning null.
So maybe its time to revisit that code.
I am unaware of what object type ClassLibrary1.Class1 is
If it is fetching values from a database, you should check the SQL statement being genereated and the actual result of it.

cheers