Object reference not set to an instance of an object

[Mahyog]

In my web project I am using FormView to Show, Edit and Delete all database details my code is as follow.

protected void Page_Load(object sender, EventArgs e)
    {
        if (!IsPostBack)
        {
            FormView1.AllowPaging = true;
            FormView1.PagerSettings.PageButtonCount = 15;

            BindFormView();
        }
    }

    private void BindFormView()
    {
        using (SqlConnection conn = new SqlConnection(ConfigurationManager.ConnectionStrings["NWConnString"].ToString()))
        {
            DataSet dsCategory = new DataSet();

            string strSelectCmd = "SELECT CategoryID,CategoryName,Description FROM Categories";

            SqlDataAdapter da = new SqlDataAdapter(strSelectCmd, conn);

            conn.Open();

            da.Fill(dsCategory, "Category");


            FormView1.DataSource = dsCategory;
            FormView1.DataBind();
        }
    }

    protected void FormView1_PageIndexChanging(object sender, FormViewPageEventArgs e)
    {
        FormView1.PageIndex = e.NewPageIndex;

        BindFormView();
    }

    protected void FormView1_ItemInserting(object sender, FormViewInsertEventArgs e)
    {
        using (SqlConnection conn = new SqlConnection(ConfigurationManager.ConnectionStrings["NWConnString"].ToString()))
        {
            SqlCommand cmd = new SqlCommand();

            cmd.Connection = conn;

            cmd.CommandText = "INSERT INTO Categories ( CategoryID, CategoryName, Description, Picture ) VALUES ( @CategoryID, @CategoryName, @Description, @Picture )";

            cmd.CommandType = CommandType.Text;

            string strCategoryID = ((TextBox)FormView1.Row.FindControl("tbCategoryID")).Text;
            string strCategoryName = ((TextBox)FormView1.Row.FindControl("tbCategoryName")).Text;
            string strDescription = ((TextBox)FormView1.Row.FindControl("tbDescription")).Text;

            cmd.Parameters.Add("@CategoryID", SqlDbType.Int).Value = Convert.ToInt32(strCategoryID);
            cmd.Parameters.Add("@CategoryName", SqlDbType.NVarChar, 50).Value = strCategoryName;
            cmd.Parameters.Add("@Description", SqlDbType.NText).Value = strDescription;

            FileUpload uploadPicture = (FileUpload)FormView1.FindControl("uploadPicture");

            if (uploadPicture.HasFile)
            {
                cmd.Parameters.Add("@Picture", SqlDbType.VarBinary).Value = uploadPicture.FileBytes;
            }
            else
            {
                cmd.Parameters.Add("@Picture", SqlDbType.VarBinary).Value = DBNull.Value;
            }

            conn.Open();

            cmd.ExecuteNonQuery();
        }

        FormView1.ChangeMode(FormViewMode.ReadOnly);

        BindFormView();
    }

    protected void FormView1_ItemUpdating(object sender, FormViewUpdateEventArgs e)
    {
        using (SqlConnection conn = new SqlConnection(ConfigurationManager.ConnectionStrings["NWConnString"].ToString()))
        {
            SqlCommand cmd = new SqlCommand();

            cmd.Connection = conn;

            cmd.CommandText = "UPDATE Categories SET CategoryName = @CategoryName, Description = @Description, Picture = ISNULL(@Picture,Picture) WHERE CategoryID = @CategoryID";

            cmd.CommandType = CommandType.Text;

            string strCategoryID = ((Label)FormView1.Row.FindControl("lblCategoryID")).Text;
            string strCategoryName = ((TextBox)FormView1.Row.FindControl("tbCategoryName")).Text;
            string strDescription = ((TextBox)FormView1.Row.FindControl("tbDescription")).Text;

            cmd.Parameters.Add("@CategoryID", SqlDbType.Int).Value = strCategoryID;
            cmd.Parameters.Add("@CategoryName", SqlDbType.NVarChar, 50).Value = strCategoryName;
            cmd.Parameters.Add("@Description", SqlDbType.NText).Value = strDescription;

            FileUpload uploadPicture = (FileUpload)FormView1.FindControl("uploadPicture");

            if (uploadPicture.HasFile)
            {
                cmd.Parameters.Add("@Picture", SqlDbType.VarBinary).Value = uploadPicture.FileBytes;
            }
            else
            {
                cmd.Parameters.Add("@Picture", SqlDbType.VarBinary).Value = DBNull.Value;
            }

            conn.Open();

            cmd.ExecuteNonQuery();
        }

        FormView1.ChangeMode(FormViewMode.ReadOnly);

        BindFormView();
    }

    protected void FormView1_ItemDeleting(object sender, FormViewDeleteEventArgs e)
    {
        using (SqlConnection conn = new SqlConnection(ConfigurationManager.ConnectionStrings["NWConnString"].ToString()))
        {
            SqlCommand cmd = new SqlCommand();

            cmd.Connection = conn;

            cmd.CommandText = "DELETE FROM Categories WHERE CategoryID = @CategoryID";

            cmd.CommandType = CommandType.Text;

            string strCategoryID = ((Label)FormView1.Row.FindControl("lblCategoryID")).Text;

            cmd.Parameters.Add("@CategoryID", SqlDbType.Int).Value = strCategoryID;

            conn.Open();

            cmd.ExecuteNonQuery();
        }

        BindFormView();
    }

    protected void FormView1_ModeChanging(object sender, FormViewModeEventArgs e)
    {
        FormView1.ChangeMode(e.NewMode);

        BindFormView();
    }

and I get "Object reference not set to an instance of an object" error while Editing and Inserting record for following code.

            string strCategoryID = ((TextBox)FormView1.Row.FindControl("tbCategoryID")).Text;

Thanks.

[Frinavale]

It sounds like the FindControl method failed to find a TextBox with the ID "tbCategory ID".

Double check that the ID of TextBox in your FormView1 template is "tbCategory ID".

-Frinny

[Mahyog]

Yes thats the mistake I have made.
Thanks.