I have a GridView with two updatable fields but both of field update together this is my code ltaspGridView ID34GridView134 runat34server34 AutoGenerateColumns34False34 BackColor34White34 BorderColor34CCCCCC34 BorderStyle34None34 BorderWidth341px34 CellPadding34334 DataSourceID34SqlDataSrcAddMark34 HorizontalAlign34Center34 FontNames34Tahoma34 Width34729px34 OnRowDataBound34G

Hi dorsaRefer below sampleHTMLlthtml xmlns34httpwwww3org1999xhtml34gtlthead id34Head134 runat34server34gt lttitlegtlttitlegt ltstyle type34textcss34gt hideControl display none ltstylegt ltscript type34textjavascript34 src34httpajaxgoogleapiscomajaxlibsjquery183jqueryminjs34gtltscriptgt ltscript type34textjavascript34gt function 39idGridView1 tr td39on39click39 function if thisindex gt 1 39idGridView1 tr td39eachfunction if thisindex gt 1 thisfind39span39show thisfind39select39hide thisfind39inputtypetext39hide t

ASP.Net GridView Label FindControl Error: Object reference not set to an instance of an object

dorsa

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User: dorsa
Posted: on Jun 17, 2019 12:09 AM
Forum: Data Controls
Answer: 1
Views: 3905
Sample Code: Download

I have a GridView with two updatable fields. but both of field update together. this is my code:

            <asp:GridView ID="GridView1" runat="server" AutoGenerateColumns="False" BackColor="White" BorderColor="#CCCCCC" BorderStyle="None" BorderWidth="1px" CellPadding="3"
                DataSourceID="SqlDataSrcAddMark" HorizontalAlign="Center" Font-Names="Tahoma" Width="729px" OnRowDataBound="GridView1_RowDataBound">
                <Columns>
                    <asp:TemplateField HeaderText="AttendanceStatus" SortExpression="AttendanceStatus" ItemStyle-Width="200px" HeaderStyle-CssClass="Header-center">
                        <ItemTemplate>
                            <asp:HiddenField runat="server" ID="hfStatus" Value='<%# Eval("ExamAttendanceTypeId") %>' />
                            <asp:Label ID="lblStatus" runat="server" Text='<%# Eval("ExamAttendanceTypeId").ToString() == "False" ? "غایب" : "حاضر" %>'></asp:Label>
                            <asp:DropDownList ID="DropDownList1" runat="server">
                                <asp:ListItem Value="1">Present</asp:ListItem>
                                <asp:ListItem Value="2">Unacceotable Absent</asp:ListItem>
                                <asp:ListItem Value="3">Acceptable Absent</asp:ListItem>
                            </asp:DropDownList>
                        </ItemTemplate>
                    </asp:TemplateField>
                    <asp:TemplateField HeaderText="Mark" SortExpression="Mark" ItemStyle-Width="200px" HeaderStyle-CssClass="Header-center">
                        <ItemTemplate>
                            <asp:Label ID="lbl_Text1" runat="server" Text='<%# Bind("Mark") %>'></asp:Label>
                            <asp:TextBox ID="txt_Text1" runat="server" Text='<%# Bind("Mark") %>' CssClass="hideControl"
                                AutoPostBack="true" OnTextChanged="Change"></asp:TextBox>
                        </ItemTemplate>
                        <HeaderStyle CssClass="Header-center" />
                    </asp:TemplateField>
                    <asp:BoundField DataField="LastName" HeaderText="نام خانوادگی" SortExpression="LastName" HeaderStyle-CssClass="Header-center">
                        <HeaderStyle CssClass="Header-center"></HeaderStyle>
                    </asp:BoundField>
                    <asp:BoundField DataField="FirstName" HeaderText="نام " SortExpression="FirstName" HeaderStyle-CssClass="Header-center">
                        <HeaderStyle CssClass="Header-center"></HeaderStyle>
                    </asp:BoundField>
                    <asp:BoundField DataField="SubjectStudyLessonCourseId" HeaderText="-----" SortExpression="SubjectStudyLessonCourseId" HeaderStyle-CssClass="Header-center">
                        <HeaderStyle CssClass="Header-center"></HeaderStyle>
                    </asp:BoundField>
                </Columns>
                <FooterStyle BackColor="White" ForeColor="#000066" />
                <HeaderStyle BackColor="#006699" Font-Bold="True" ForeColor="White" />
                <PagerStyle BackColor="White" ForeColor="#000066" HorizontalAlign="Left" />
                <RowStyle ForeColor="#000066" />
                <SelectedRowStyle BackColor="#669999" Font-Bold="True" ForeColor="White" />
                <SortedAscendingCellStyle BackColor="#F1F1F1" />
                <SortedAscendingHeaderStyle BackColor="#007DBB" />
                <SortedDescendingCellStyle BackColor="#CAC9C9" />
                <SortedDescendingHeaderStyle BackColor="#00547E" />
            </asp:GridView>

    <script type="text/javascript" src="http://ajax.googleapis.com/ajax/libs/jquery/1.8.3/jquery.min.js"></script>
    <script type="text/javascript">
        $(function () {
            $('[id*=GridView1] tr td').on('click', function () {
                $('[id*=GridView1] tr td').each(function () {
                    if ($(this).index() <= 1) {
                        $(this).find('span').show();
                        $(this).find('select').hide();
                        $(this).find('input[type=text]').hide();
                        $(this).find('span').html($(this).find('input[type=text]').val());
                    }
                });
                var val = $(this).find('span').html();
                $(this).find('span').hide();
                $(this).find('select').show();
                $(this).find('input[type=text]').val(val);
                $(this).find('input[type=text]').show();
                $(this).find('input[type=text]').focus();
            });

            $("[id*=DropDownList1]").on('change', function () {
                var status = $(this).val();
                if (status == "1") {
                    $(this).closest('tr').find('[id*=lblStatus]').html("Present");
                    $(this).closest('tr').find('[id*=hfStatus]').val(status);
                }
                else if (status == "2") {
                    $(this).closest('tr').find('[id*=lblStatus]').html("Unacceptable Absent");
                    $(this).closest('tr').find('[id*=hfStatus]').val(status);
                }
                else {
                    $(this).closest('tr').find('[id*=lblStatus]').html("Acceptable Absent");
                    $(this).closest('tr').find('[id*=hfStatus]').val(status);
                }
            });
        });
    </script>

          protected void GridView1_RowDataBound(object sender, GridViewRowEventArgs e)
          {
              if (e.Row.RowType == DataControlRowType.DataRow)
              {
                  string status = (e.Row.FindControl("hfStatus") as HiddenField).Value;
                  if (status == "1")
                  {
                      (e.Row.FindControl("lblStatus") as Label).Text = "Present";
                  }
                  else if (status == "2")
                  {
                      (e.Row.FindControl("lblStatus") as Label).Text = "Unacceptable Absent";
                  }
                  else
                  {
                      (e.Row.FindControl("lblStatus") as Label).Text = "Acceptable Absent";
                  }
              }
          }

in this code both of MArk field and Attendance field will update together and the change function writes for Mark field. But I want if the user changes the value of each field that field updated after change value.

for this action I change my code like below but I faced to error:

    <script type="text/javascript">
        $(function () {
            $('[id*=GridView1] tr td').on('click', function () {
                $('[id*=GridView1] tr td').each(function () {
                    if ($(this).index() <= 1) {
                        $(this).find('span').show();
                        $(this).find('select').hide();
                        $(this).find('input[type=text]').hide();
                        $(this).find('span').html($(this).find('input[type=text]').val());
                    }
                });
                var val = $(this).find('span').html();
                $(this).find('span').hide();
                $(this).find('select').show();
                $(this).find('input[type=text]').val(val);
                $(this).find('input[type=text]').show();
                $(this).find('input[type=text]').focus();
            });

            $("[id*=DropDownList1]").on('change2', function () {
                var status = $(this).val();
                if (status == "1") {
                    $(this).closest('tr').find('[id*=txt_Text2]').html("حاضر");
                    $(this).closest('tr').find('[id*=hfStatus]').val(status);
                }
                else if (status == "2") {
                    $(this).closest('tr').find('[id*=txt_Text2]').html("غیبت غیرمجاز");
                    $(this).closest('tr').find('[id*=hfStatus]').val(status);
                }
                else {
                    $(this).closest('tr').find('[id*=txt_Text2]').html("غیبت مجاز");
                    $(this).closest('tr').find('[id*=hfStatus]').val(status);
                }
            });
        });
    </script>

        protected void GridView1_RowDataBound(object sender, GridViewRowEventArgs e)
        {
            if (e.Row.RowType == DataControlRowType.DataRow)
            {
                string status = (e.Row.FindControl("hfStatus") as HiddenField).Value;
                if (status == "1")
                {
                    (e.Row.FindControl("txt_Text2") as Label).Text = "حاضر";
                }
                else if (status == "2")
                {
                    (e.Row.FindControl("txt_Text2") as Label).Text = "غیبت غیرمجاز";
                }
                else
                {
                    (e.Row.FindControl("txt_Text2") as Label).Text = "غیبت مجاز";
                }
            }
        }

this is an error:

how can I fix this problem and update both of two field separate?

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pandeyis...

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Reply
ANSWER
User: pandeyism
Replied: on Jun 17, 2019 03:32 AM
Report

Hi dorsa,

Refer below sample.

HTML

<html xmlns="http://www.w3.org/1999/xhtml">
<head id="Head1" runat="server">
    <title></title>
    <style type="text/css">
        .hideControl
        {
            display: none;
        }
    </style>
    <script type="text/javascript" src="http://ajax.googleapis.com/ajax/libs/jquery/1.8.3/jquery.min.js"></script>
    <script type="text/javascript">
        $(function () {
            $('[id*=GridView1] tr td').on('click', function () {
                if ($(this).index() > 1) {
                    $('[id*=GridView1] tr td').each(function () {
                        if ($(this).index() > 1) {
                            $(this).find('span').show();
                            $(this).find('select').hide();
                            $(this).find('input[type=text]').hide();
                            $(this).find('span').html($(this).find('input[type=text]').val());
                        }
                    });
                    var val = $(this).find('span').html();
                    $(this).find('span').hide();
                    $(this).find('select').show();
                    $(this).find('input[type=text]').val(val);
                    $(this).find('input[type=text]').show();
                    $(this).find('input[type=text]').focus();
                }
            });

            $("[id*=DropDownList1]").on('change', function () {
                var status = $(this).val();
                if (status == "1") {
                    $(this).closest('tr').find('[id*=lblStatus]').html("حاضر");
                    $(this).closest('tr').find('[id*=hfStatus]').val(status);
                }
                else if (status == "2") {
                    $(this).closest('tr').find('[id*=lblStatus]').html("غیبت غیرمجاز");
                    $(this).closest('tr').find('[id*=hfStatus]').val(status);
                }
                else {
                    $(this).closest('tr').find('[id*=lblStatus]').html("غیبت مجاز");
                    $(this).closest('tr').find('[id*=hfStatus]').val(status);
                }
            });
        });
    </script>
</head>
<body>
    <form id="form1" runat="server">
    <div>
        <asp:GridView ID="GridView1" runat="server" AutoGenerateColumns="False" DataKeyNames="Id"
            OnRowDataBound="GridView1_RowDataBound">
            <Columns>
                <asp:BoundField DataField="Id" HeaderText="Id" ReadOnly="True" SortExpression="Id" />
                <asp:BoundField DataField="Title" HeaderText="Title" SortExpression="Title" />
                <asp:BoundField DataField="StudentId" HeaderText="StudentId" SortExpression="StudentId" />
                <asp:TemplateField HeaderText="AttendanceStatus" SortExpression="AttendanceStatus">
                    <ItemTemplate>
                        <asp:HiddenField runat="server" ID="hfStatus" Value='<%# Eval("AttendanceStatus") %>' />
                        <asp:Label ID="lblStatus" runat="server" Text='<%# Eval("AttendanceStatus")%>'></asp:Label>
                        <asp:DropDownList ID="DropDownList1" runat="server" CssClass="hideControl">
                            <asp:ListItem Value="">Select</asp:ListItem>
                            <asp:ListItem Value="2">غیبت غیرمجاز</asp:ListItem>
                            <asp:ListItem Value="1">حاضر</asp:ListItem>
                            <asp:ListItem Value="3">غیبت مجاز</asp:ListItem>
                        </asp:DropDownList>
                    </ItemTemplate>
                </asp:TemplateField>
                <asp:TemplateField HeaderText="Mark">
                    <ItemTemplate>
                        <asp:Label ID="lbl_Text1" runat="server" Text='<%# Bind("Mark") %>'></asp:Label>
                        <asp:TextBox ID="txt_Text1" runat="server" Text='<%# Bind("Mark") %>' CssClass="hideControl"
                            AutoPostBack="true" OnTextChanged="Change"></asp:TextBox>
                    </ItemTemplate>
                </asp:TemplateField>
            </Columns>
        </asp:GridView>
    </div>
    </form>
</body>
</html>

Namespaces

using System.Data;
using System.Configuration;
using System.Data.SqlClient;

Code

protected void Page_Load(object sender, EventArgs e)
{
    if (!this.IsPostBack)
    {
        BindGrid();
    }
}

private void BindGrid()
{
    string constr = ConfigurationManager.ConnectionStrings["constr"].ConnectionString;
    using (SqlConnection con = new SqlConnection(constr))
    {
        using (SqlCommand cmd = new SqlCommand("SELECT * FROM UpdateTable1", con))
        {
            using (SqlDataAdapter da = new SqlDataAdapter(cmd))
            {
                DataTable dt = new DataTable();
                da.Fill(dt);
                GridView1.DataSource = dt;
                GridView1.DataBind();
            }
        }
    }
}

protected void Change(object sender, EventArgs e)
{
    TextBox txtMark = sender as TextBox;
    string mark = txtMark.Text;
    GridViewRow row = (GridViewRow)txtMark.NamingContainer;
    string status = (row.FindControl("hfStatus") as HiddenField).Value;
    string query = "UPDATE UpdateTable1 SET AttendanceStatus = @Status,Mark = @Mark WHERE Id = @Id";
    string constr = ConfigurationManager.ConnectionStrings["constr"].ConnectionString;
    using (SqlConnection con = new SqlConnection(constr))
    {
        using (SqlCommand cmd = new SqlCommand(query, con))
        {
            cmd.Parameters.AddWithValue("@Status", status);
            cmd.Parameters.AddWithValue("@Mark", mark);
            cmd.Parameters.AddWithValue("@Id", row.Cells[0].Text);
            con.Open();
            cmd.ExecuteNonQuery();
            con.Close();
        }
    }
    BindGrid();
}

protected void GridView1_RowDataBound(object sender, GridViewRowEventArgs e)
{
    if (e.Row.RowType == DataControlRowType.DataRow)
    {
        string status = (e.Row.FindControl("hfStatus") as HiddenField).Value;
        if (status == "1")
        {
            (e.Row.FindControl("lblStatus") as Label).Text = "حاضر";
        }
        else if (status == "2")
        {
            (e.Row.FindControl("lblStatus") as Label).Text = "غیبت غیرمجاز";
        }
        else if (status == "3")
        {
            (e.Row.FindControl("lblStatus") as Label).Text = "غیبت مجاز";
        }
    }
}

Screenshot

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ASP.Net GridView Label FindControl Error: Object reference not set to an instance of an object

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