Object reference not set to an instance of the Object

Hi Amit

  In Add I have written below code but it is returning Null . I have entered date in this row

if(gr.Cells[0].Text == "70")
{
    TextBox txtDynamic = gr.FindControl("txtSessionDate") as TextBox;
    if (txtDynamic != null)
    {
        sessionDate = txtDynamic.Text;
    }
}

Thanks

Hi Amit

  I have below code . Even if enter Data in one of the rows it is not retreiving. Add functionality is not able to retreive TextBox value.

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;
        txtSessionDate = (TextBox)e.Row.FindControl("txtSessionDate");
    }
}

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)
            {

                TextBox txtDynamic = gr.FindControl("txtSessionDate") as TextBox;
                if (txtDynamic != null)
                {
                    sessionDate = txtDynamic.Text;
                }
            }
        }
    }
}

SQLUtility sQLUtility = new SQLUtility();
DataTable dt = sQLUtility.GeBookPlanningRecommendation(HRpl, BookCollection, StudentCollection).Tables[0];
if (dt != null)
{
    DataColumn Remarks = new DataColumn("Remarks", typeof(string));
    dt.Columns.Add(Remarks);
    DataColumn Dates = new DataColumn("SessionDate", typeof(string));
    dt.Columns.Add(Dates);
}

Thanks

Try this

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

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

protected void linkAdd_Click(object sender, EventArgs e)
{
    try
    {
        foreach (GridViewRow row in gr.Rows)
        {
            if (row.RowType == DataControlRowType.DataRow)
            {
                TextBox txtDynamic = row.FindControl("txtSessionDate") as TextBox;
                if (txtDynamic != null)
                {
                    string dynamicValue = txtDynamic.Text;
                    // Do something with the dynamicValue
                }
            }
        }
    }
    catch { }
}

Hi AMit

  When i write this line i get below error - e.Row.DataItem = txtSessionDate;

DataBinding System.Web.UI.WebControls.TextBox does not contain a property with the name Remarks.

Thanks

Hi AMit

  o.k But how in below code i will get SessionDate value in a variable

protected void lnkAdd_Click(object sender, EventArgs e)
        {
            try
            {

                foreach (GridViewRow gr in grdPlanning.Rows)
                {
                    if (gr.RowType == DataControlRowType.DataRow)
                    {
}
}
}
}

Thanks

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

The above code creates a new TextBox control, sets its properties, and adds it to the GridView row. But, when you try to access this TextBox control later in the code using the FindControl method, it returns null. Because the FindControl method only searches for controls that were added to the page declaratively, i.e., controls that were defined in the .aspx markup. But you are adding the TextBox control dynamically in code-behind, it is not part of the page's control hierarchy, and FindControl cannot find it.

Hi AMit

  If i am adding Textbox Control then why it is showing NULL.

Thanks

You can check if txtSessionDate is not null before attempting to set its Enabled property.

if (Remark == "Done" || Remark == "Scheduled")
{
    if (txtSessionDate != null)
    {
        txtSessionDate.Enabled = false;
    }
}