show a message box if gridview checkbox doesn't select in asp.net

Question

User-1092307275 posted

I have a <g class="gr_ gr_32 gr-alert gr_spell gr_inline_cards gr_run_anim ContextualSpelling" id="32" data-gr-id="32">gridview</g> that has a checkbox in it. I want to delete the rows of <g class="gr_ gr_139 gr-alert gr_spell gr_inline_cards gr_run_anim ContextualSpelling" id="139" data-gr-id="139">gridview</g> that checkbox of them was selected.and if the user doesn't check any checkbox the error message shown to the user. and before deleting the data, Ask the user if they are sure of the operation?

 foreach (GridViewRow gvr in GridView1.Rows)
            {
                if (((CheckBox)gvr.FindControl("chkDelete")).Checked == true)
                {
                    Button2.Attributes.Add("onclick", "javascript:return del()");
                    //delet the value of selected row from EDU_CourseSessionPlan table
                    SqlDataReader dr2;
                    con.Open();
                    sqlcom.Connection = con;
                    sqlcom.CommandText = "delete  from EDU_CourseSessionPlan where CourseId='" + Int32.Parse(LblLessonId2.Text) + "'";
                    dr2 = sqlcom.ExecuteReader(CommandBehavior.SingleRow);
                    if (dr2.Read())
                    {
                        validate1 = true;
                    }
                    con.Close();
                    //delet the value of selected row from EDU_EDU_Course table

                    SqlDataReader dr3;
                    con.Open();
                    sqlcom.Connection = con;
                    sqlcom.CommandText = "delete  from EDU_Course where Id='" + Int32.Parse(LblLessonId2.Text) + "'";
                    dr3 = sqlcom.ExecuteReader(CommandBehavior.SingleRow);
                    if (dr3.Read())
                    {
                        validate1 = true;
                    }
                    con.Close();

                    string myStringVariable = "Your information has been successfully deleted";
                    ClientScript.RegisterStartupScript(this.GetType(), "myalert", "alert('" + myStringVariable + "');", true);

                    ///// refresh the data of Gridview1
                    Response.Redirect("ShowCourse.aspx?Value1=" + LblSubjectStudy.Text);
                }
                else
                {
                    ScriptManager.RegisterStartupScript(this, this.GetType(), "alert", "alert('please checked the rows that you want to delet');", true);
                }
            }

    <script type="text/javascript">
        function del()
        {
            var c = confirm("Are you sure you want to remove the selected field?");
            if (c)
            {
                return true;
            }
            else
            {
                return false;
            }
        }
    </script>

<asp:GridView ID="GridView2" runat="server" EmptyDataText="هیچ واحدی تعریف نشده است" DataKeyNames="Code" AutoGenerateColumns="False" Width="932px" 
                            BackColor="White" BorderColor="#CCCCCC" BorderStyle="None" BorderWidth="1px" CellPadding="3" Font-Names="Tahoma" 
                            OnSelectedIndexChanged="GridView2_SelectedIndexChanged" OnDataBound="GridView2_DataBound">
                         <Columns>
                       
                             <asp:BoundField DataField="TRoom" HeaderText="نام اتاق"  HeaderStyle-CssClass="header-center" />
                             <asp:BoundField DataField="DayWeek" HeaderText="روز هفته"  HeaderStyle-CssClass="header-center" />
                             <asp:BoundField DataField="ET" HeaderText="ساعت پایان کلاس"  HeaderStyle-CssClass="header-center" />
                             <asp:BoundField DataField="ST" HeaderText="ساعت شروع کلاس"   HeaderStyle-CssClass="header-center"/>
                             <asp:BoundField DataField="LNProfessor" HeaderText="نام خانوادگی استاد"  HeaderStyle-CssClass="header-center" />
                             <asp:BoundField DataField="NProfessor" HeaderText="نام استاد"  HeaderStyle-CssClass="header-center" />
                             <asp:BoundField DataField="TLesson" HeaderText="نام درس"   HeaderStyle-CssClass="header-center"/>
                             <asp:BoundField DataField="Code" HeaderText="کد درس"   HeaderStyle-CssClass="header-center"/>
                             
                             <asp:TemplateField HeaderText="انتخاب">
                                <ItemTemplate>
                                    <asp:CheckBox ID="chkDelete" runat="server" Checked='<%# Convert.ToBoolean(Eval("IsChecked").ToString()) %>'
                                         AutoPostBack="true" />
                                </ItemTemplate>
                            </asp:TemplateField>
                         </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>

but when I run my program I'm having this problem:

Answer 1

User-943250815 posted

To get a control on gridview, you have to first get Row then find control on Row.Cells.
Bellow a short foreach version

foreach (GridViewRow zRow in grdNFE.Rows) {
    if ((zRow.RowType == DataControlRowType.DataRow)) {
        zChkBoxItem = ((CheckBox)(zRow.Cells[0].FindControl("chkItem"))); 
        if (zChkBoxItem.Checked) {
            //  Do what you need here
        }
        
    }
    
}

Answer 2

User-893317190 posted

Hi dorsa2,

GridView 's row has a property named RowType, which shows its type(Header,Foot,DataRow,) .

Your checkbox only exists in row of Type DataRow ,so  you should choose datarow first(In header row , there is no checkbox, only header of your gridview)

You could write your code as follows.

  foreach (GridViewRow row in GridView1.Rows)
            {
                if (row.RowType == DataControlRowType.DataRow)
                {
                    //write your code
                }
            }

Best regards,

Ackerly Xu

Answer 3

User-1092307275 posted

Thx Dear jzero for your guidance,

what is zChkBoxItem ?!

Answer 4

User-943250815 posted

Sorry, I used a vb > c# converter

zChkBoxItem is just a variable to store your checkbox control, so I have all checkbox properties on hand including "Checked"