Object reference not set to an instance of the Object

Ramco if i may

The code line e.Row.DataItem = txtSessionDate; is trying to assign a value to the DataItem property of a GridViewRow object, which is represented by the variable e.Row.

Hi Naimish

  What does this line does

e.Row.DataItem = txtSessionDate;

Thanks

The error "Object reference not set to an instance of the object" typically occurs when you try to use an object that has not been instantiated. In the code you provided, the error could be caused by several factors, including:

1. The variable "gr.DataItem" in the lnkAdd_Click method may be null, causing an exception when ToString() method is called.

2. The txtSessionDate control may not have been initialized in the gr_RowDataBound method.

3. The DataItem property of the GridViewRowEventArgs parameter in the gr_RowDataBound method may be null, causing an exception when it is accessed.

To fix the issue, you could add some null checks before using the objects, like the following:

protected void lnkAdd_Click(object sender, EventArgs e)
{
    try
    {
        //string sessionDate = "";
        Boolean success = false;

        BALGroup objGroup = new BALGroup();
        Group Result = objGroup.GetGroupDetail(Convert.ToInt32(hdfGroupId.Value));

        foreach (GridViewRow gr in grdPlanning.Rows)
        {
            if (gr.RowType == DataControlRowType.DataRow)
            {
                if (gr.DataItem != null)
                {
                    string sessionDate = gr.DataItem.ToString();
                    if (sessionDate != null)
                    {
                        //...
                    }
                }
            }
        }
    }
    catch (Exception ex)
    {
        // Handle the exception
    }
}

protected void gr_RowDataBound(object sender, GridViewRowEventArgs e)
{
    try
    {
        if (e.Row.RowType != DataControlRowType.DataRow)
            return;

        e.Row.Cells[0].HorizontalAlign = HorizontalAlign.Center;

        TextBox txtSessionDate = new TextBox();
        txtSessionDate.Text = "";
        txtSessionDate.CssClass = "form-control daterange-single";
        e.Row.Cells[10].Controls.Add(txtSessionDate);
        e.Row.Cells[10].HorizontalAlign = HorizontalAlign.Center;

        string Remark = DataBinder.Eval(e.Row.DataItem, "Remarks")?.ToString();
        if (Remark == "Done" || Remark == "Scheduled")
        {
            if (txtSessionDate != null)
            {
                txtSessionDate.Enabled = false;
            }
        }

        if (txtSessionDate != null)
        {
            e.Row.DataItem = txtSessionDate;
        }
    }
    catch (Exception ex)
    {
        // Handle the exception
    }
}

Thanks