Object reference not set to an instance of an object

Question

hello can any one help me :)

whats the problem in this code ??

protected void LinkButton1_Click(object sender, EventArgs e)
{
    //object o = new object();
    //Control co = new Control();
    //co = GridView1.FindControl("EmpFileUpload");
    FileUpload f = new FileUpload();
    (System.Web.UI.WebControls.FileUpload)f = (System.Web.UI.WebControls.FileUpload)(GridView1.FindControl("EmpFileUpload"));

    if (f.HasFile)
    {
        SqlConnection conn = new SqlConnection(ConfigurationManager.ConnectionStrings["schoolsConnectionString"].ConnectionString);
        conn.Open();
        SqlCommand insertCommand = new SqlCommand("insert_Empimg", conn);

        insertCommand.Parameters.Add("Emp_imgPath", SqlDbType.NVarChar, 0).Value =f.FileName;

        insertCommand.CommandType = CommandType.StoredProcedure;
        insertCommand.ExecuteNonQuery();

        conn.Close();
    }



}

It is difficult to know just by looking at the code. You should look at the exception's stack trace, and find out which line is exactly throwing the exception. — aliensurfer
– aliensurfer, Commented May 10, 2011 at 11:41
Welcome to Stackoverflow! Let me give you some hints that might help you get good answers to your question: (a) If you get an error message, tell us in which line of your code this error occurs (this usually shown by Visual Studio). (b) Please format your code. This has been done by Richard for your right now; next time, please do it yourself. — Heinzi
– Heinzi, Commented May 10, 2011 at 11:41

Antony Woods · Accepted Answer · 2011-05-10 11:41:54Z

1

Firstly

FileUpload f = new FileUpload();
(System.Web.UI.WebControls.FileUpload)f = (System.Web.UI.WebControls.FileUpload(GridView1.FindControl("EmpFileUpload"));

You don't need to 'new' f if you're reassigning it on the next line.

FileUpload f = (System.Web.UI.WebControls.FileUpload(GridView1.FindControl("EmpFileUpload"));

Secondly, you need to check f isn't null by the sounds of it.

if(f != null && f.HasFile)

answered May 10, 2011 at 11:41

Antony Woods

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Comments

Richard Friend · Accepted Answer · 2011-05-10 11:44:53Z

1

It's possible that your FindControl is not finding the upload control.

Lets tidy this code up a bit..

//You dont need the `new` as you are assigning to the result of `FindControl`
FileUpload f = GridView1.FindControl("EmpFileUpload") as FileUpload;

//Check for null here, this is probably your problem
if (f !=null && f.HasFile)     
{       
    //Using statement takes care of closing our connection and disposing our objects.
    using (SqlConnection conn = new SqlConnection(ConfigurationManager.ConnectionStrings["schoolsConnectionString"].ConnectionString))
    {
         conn.Open();         
         using (SqlCommand insertCommand = new SqlCommand("insert_Empimg", conn))
         {          
             insertCommand.Parameters.Add("Emp_imgPath", SqlDbType.NVarChar, 0).Value =f.FileName;          
             insertCommand.CommandType = CommandType.StoredProcedure;         
             insertCommand.ExecuteNonQuery();
         }
    }
}

Then we can have a look at why it is not being found, could you paste your markup that declares your EmpFileUpload

answered May 10, 2011 at 11:44

Richard Friend

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1 Comment

Chad Over a year ago

And you may need to find the row of the control you are looking for and do a find control there. Gridviews can be picky about it. There could but several controls in a gridview with that id. But only one in any given row.

Anyname Donotcare · Accepted Answer · 2011-05-10 13:44:54Z

0

FileUpload f = (System.Web.UI.WebControls.FileUpload)(GridView1.FindControl("EmpFileUpload"));

And finding the control by GridView1.FindControl("EmpFileUpload") depends on where you put your file upload in the grid view . please put your aspx shot to identify clearly where you put your control.to access it in the correct way.

answered May 10, 2011 at 13:44

Anyname Donotcare

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