Required field is not validating my text box in asp.net

Question

I have created a user control and used group validation in it but i am new to group validation , i know how required field works but in validation group i am not able to use required filed validator of my own . There is some custom validator which are working on client side using javascript. please guide me how can use combination of custom validator ,validation group and javascript to show error message using js

<cc1:ModalPopupExtender ID="ModalPopupExtender2" Y="20" X="10" runat="server" TargetControlID="Button2"
    PopupControlID="pnlAddMoreOrEdit" BackgroundCssClass="ModalPoopup" BehaviorID="popup1"
    CancelControlID="modalCancel" PopupDragHandleControlID="EmptyPanel" RepositionMode="none">
</cc1:ModalPopupExtender>
 <%: System.Web.Optimization.Scripts.Render("~/Script/BusinessIncome44ADA")%>
<%--<script src="../../ITR_FY1617Assets/scripts/BusinessIncome44ADA.js" type="text/javascript"></script>--%>
<asp:Panel ID="pnlAddMoreOrEdit" runat="server" CssClass="ModalPopupPanel" Style="width: 900px;
    display: none">
    <div class="ModalHeader">
        <asp:Label ID="lblAdd" runat="server" CssClass="msg" Text="Business Income"></asp:Label>
        <asp:LinkButton ID="LinkButton1" runat="server" CssClass="HeaderButton CGHeaderImage"
            CausesValidation="false" OnClientClick="return Close();"  style="background-image:url('../../images/close_pop.png');" />
    </div>
    <div class="ModalBody">
        <div id="StepFive">
        </div>
        <div class="uspace">
            <asp:ValidationSummary runat="server" ID="ValidationSummary1" ForeColor="" CssClass="ValidationSummary"
                HeaderText=" Sorry, We need following information(s) to proceed further." ValidationGroup="G1">
            </asp:ValidationSummary>            
            <div id="Step1">
                <div class="Information">
                    <p>
                        Fill in the information of business income :
                    </p>
                </div>


                <p id="SubCatP" runat="server" style="display:none">
                    Suitable Area of Business 
                    <asp:DropDownList ID="ddlSubCatP" runat="server" CssClass="DropDownList" onchange="RemoveColour(this)">
                        <asp:ListItem Selected="True" Value="0">Select</asp:ListItem>
                        <asp:ListItem Value="0601">Legal</asp:ListItem>
                        <asp:ListItem Value="0602">Medical</asp:ListItem>
                        <asp:ListItem Value="0603">Engineering or Architectural</asp:ListItem>
                        <asp:ListItem Value="0604">Accountancy</asp:ListItem>
                        <asp:ListItem Value="0605">Technical</asp:ListItem>
                        <asp:ListItem Value="0606">Interior decoration</asp:ListItem>
                        <asp:ListItem Value="06071">Authorised Representative</asp:ListItem>
                        <asp:ListItem Value="06072">Film Artist </asp:ListItem>
                        <asp:ListItem Value="06073">Company Secretary</asp:ListItem>
                        <asp:ListItem Value="06074">Professional of Information Technology</asp:ListItem>

                        <asp:ListItem Value="06077">Others</asp:ListItem>
                    </asp:DropDownList>
                </p>

                <p class="RBLPara">
                    Name of Trade 
                    <asp:TextBox ID="txtNT" autocomplete="off" runat="server" MaxLength="100" CssClass="SimpleTextBox FloatRight IE6TextBox" onkeyup="RemoveColour(this)"/>
                </p>
            </div>
            <div id="Step2">

                <div id="ADDetails" style="display: none" runat="server">
                    <div class="Information">
                        <p>
                            Fill in the following information :
                        </p>
                    </div>
                    <p>
                        <span id="GrossTurnOver" runat="server">Gross Turnover / Receipts   
                        </span> 
                        <asp:TextBox ID="txtGTO" runat="server" autocomplete="off" onkeypress="return AllowNum(event);"  MaxLength="8" style="background-image: url('../../images/Rs_Symbol.png');
                            background-repeat:no-repeat;background-position: 5px;text-align: right;" CssClass="SimpleTextBox FloatRight IE6TextBox" onkeyup="checkGTO(this)" onblur="calProfit()"/>
                    </p>
                    <p id="Expense" runat="server" style="display:none">
                        Expenses
                        <asp:TextBox ID="txtExpenses" runat="server" autocomplete="off" onkeypress="return AllowNum(event);"  MaxLength="8" style="background-image: url('../../images/Rs_Symbol.png');
                            background-repeat:no-repeat;background-position: 5px;text-align: right;" CssClass="SimpleTextBox FloatRight IE6TextBox" onkeyup="checkGTO(this)" onblur="calProfit()"/>
                    </p>
                    <p>
                        <span id="NetProf" runat="server">Net Profit / Income
                        </span>
                        <asp:TextBox ID="txtIncome" runat="server" ValidationGroup="G3" autocomplete="off" onkeypress="return AllowNegNum(event);"  MaxLength="8" style="background-image: url('../../images/Rs_Symbol.png');
                            background-repeat:no-repeat;background-position: 5px;text-align: right;" CssClass="SimpleTextBox FloatRight IE6TextBox" onkeyup="checkGTO(this)" />
                    </p>
                </div>

                <div class="SundryDetails" id="SundryDetails" runat="server" style="display: none">
                    <p runat="server">
                        Sundry Debtors
                        <asp:TextBox ID="txtSD" autocomplete="off" runat="server" placeholder="If any" onkeypress="return AllowNum(event);"  MaxLength="8" style="background-image: url('../../images/Rs_Symbol.png');
                            background-repeat:no-repeat;background-position: 5px;text-align: right;" CssClass="SimpleTextBox FloatRight IE6TextBox" />
                    </p>
                    <p runat="server">
                        Sundry Creditors
                        <asp:TextBox ID="txtSC" autocomplete="off" runat="server" placeholder="If any" onkeypress="return AllowNum(event);" style="background-image: url('../../images/Rs_Symbol.png');
                            background-repeat:no-repeat;background-position: 5px;text-align: right;"  MaxLength="8" CssClass="SimpleTextBox FloatRight IE6TextBox" />
                    </p>
                    <p id="StockInTrade" runat="server">
                        Stock in Trade
                        <asp:TextBox ID="txtST" autocomplete="off" runat="server" placeholder="If any" onkeypress="return AllowNum(event);"  MaxLength="8" style="background-image: url('../../images/Rs_Symbol.png');
                            background-repeat:no-repeat;background-position: 5px;text-align: right;" CssClass="SimpleTextBox FloatRight IE6TextBox" />
                    </p>
                    <p runat="server">
                        Cash Balance
                        <asp:TextBox ID="txtCB" autocomplete="off" runat="server" placeholder="If any" onkeypress="return AllowNum(event);"  MaxLength="8" style="background-image: url('../../images/Rs_Symbol.png');
                            background-repeat:no-repeat;background-position: 5px;text-align: right;" CssClass="SimpleTextBox FloatRight IE6TextBox" />
                    </p>
                </div>
            </div>
            <div id="Step3" style="display:none">
               <div class="Information">
                    <p>
                        You are required to fill Books of accounts 
                    </p>
                </div>
            </div>

        </div>
    </div>
     <div class="ModalFooter" id="footer" runat="server">
          <a id="modalBack" class="modal" style="display: none" runat="server" causesvalidation="false"
            onclick="return GoBack();">Go Back</a> 

        <a id="modalCancel" class="modal" runat="server" onclick="return Close();">Cancel</a>
        <a id="modalSave" class="modal" runat="server" onserverclick="Save" onclick="return NextStep();">Next Step</a>
        <a id="modalTemp" class="modal" runat="server" style="display: none">Saving..</a>
        <div id="mycss" style="background-color: #f2f2f2;height:15px;display:none;margin-bottom:20px;">
    <a id="A1" class="modal" style="background-color: #5fb336;float:right;color:white;padding:10px;" runat="server"  href="BusinessIncomeBookOfAC.aspx">Continue to Books Of Accounts</a>
       </div>
    </div>
    <asp:Button ID="Button2" runat="server" Style="display: none" Text="Button" />
</asp:Panel>
<asp:Panel ID="EmptyPanel" runat="server">
</asp:Panel>
<asp:HiddenField ID="hfSteps" runat="server" Value="0" />
<asp:HiddenField ID="hfId" runat="server" Value="0" />
<asp:HiddenField ID="hfadmore" Value="1" runat="server" />
<asp:HiddenField ID="hfErrordiv" Value="0" runat="server" />
<asp:HiddenField ID="hfPan" runat="server" Value="" />


<asp:CustomValidator ID="CV1" runat="server" ValidationGroup="G1"
    ClientValidationFunction="Validate_FreeLance" ForeColor="White"
    ErrorMessage="Please Select Sub Category">*</asp:CustomValidator>



<asp:CustomValidator ID="CV2" runat="server" ValidationGroup="G2"
     ClientValidationFunction="Validate_Business" ForeColor="White"
    ErrorMessage="Please Select Suitable Area of Business.">*</asp:CustomValidator>

<asp:RequiredFieldValidator  runat="server" ControlToValidate="txtNT"
  ID="RequiredFieldValidator1" ValidationGroup="G1" ForeColor="White" ErrorMessage="Please Provide Name of Trade.">*</asp:RequiredFieldValidator>

<asp:RequiredFieldValidator  runat="server" ControlToValidate="txtIncome"
  ID="as" ValidationGroup="G3" ForeColor="White" ErrorMessage="Please Provide Name of Trade.">*</asp:RequiredFieldValidator>


<asp:RequiredFieldValidator ID="RequiredFieldValidator7" runat="server" ControlToValidate="txtGTO"
                ValidationGroup="G3" ForeColor="White" ErrorMessage="Please Provide Gross Turn Over." >*</asp:RequiredFieldValidator>

<asp:RequiredFieldValidator ID="a8" runat="server" ControlToValidate="txtIncome"
                ValidationGroup="G3" ForeColor="White" ErrorMessage="Please Provide Income.">*</asp:RequiredFieldValidator>
<%--<asp:CustomValidator ID="CustomValidator11" runat="server" ValidationGroup="G3"
     ClientValidationFunction="Validate_Income" ForeColor="red">*</asp:CustomValidator>--%>

Answer 1

You have to mention the ValidationGroup in your button also

     <asp:Button ID="Button2" runat="server" Style="display: none" Text="Button" ValidationGroup="G1"  />

for example when you have to validate something in submit button click give same group to the controls you given for submit.