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HTML Required field not working as needed

In am using htm required="required" validation but it is not working properly as needed.
I have 2 button on single page and I want that on 1 button click it validate for textbox1 and on click of 2nd button it will validate for textbox2.
Please review attached image for more detail

You are looking for ValidationGroup. By giving a collection of Validators and a Button the same id, the corresponding button will only validate those fields.
<asp:TextBox ID="TextBox1" runat="server"></asp:TextBox>
<asp:RequiredFieldValidator ID="RequiredFieldValidator1" runat="server" ErrorMessage="RequiredFieldValidator" ControlToValidate="TextBox1" ValidationGroup="group1"></asp:RequiredFieldValidator>
<asp:TextBox ID="TextBox2" runat="server"></asp:TextBox>
<asp:RequiredFieldValidator ID="RequiredFieldValidator2" runat="server" ErrorMessage="RequiredFieldValidator" ControlToValidate="TextBox2" ValidationGroup="group1"></asp:RequiredFieldValidator>
<asp:Button ID="Button1" runat="server" Text="Button Group 1" ValidationGroup="group1" />
<asp:TextBox ID="TextBox3" runat="server"></asp:TextBox>
<asp:RequiredFieldValidator ID="RequiredFieldValidator3" runat="server" ErrorMessage="RequiredFieldValidator" ControlToValidate="TextBox3" ValidationGroup="group2"></asp:RequiredFieldValidator>
<asp:Button ID="Button2" runat="server" Text="Button Group 2" ValidationGroup="group2" />

I don't think HTML does that natively (grouped validation).
If server-side is not an option, then you'll need to use some JavaScript.
I have found some inspiration in this answer for a related question (Triggering HTML5 Form Validation) : https://stackoverflow.com/a/39689115/370786
If you group each set of inputs that you want to validate together in a form (so you will have several forms), then you can trigger validation through Javascript. Then you can stop the form from posting. This can be done through Javascript - maybe it can be done in HTML but I'm not sure.
Then once everything has validated you will need to post the data to the server, using some Javascript. It might be as simple as just triggering the submit() method on a form element.

Compare validator is getting active on any click

<asp:ComboBox ID="ddlto" runat="server" IncrementalFilteringMode="StartsWith"
DataSourceID="XmlDatasource1" TextField="name" ValueField="name"
Width="100%" DataTextField="name" DataValueField="name" MaxLength="0" style="display: inline;"
AutoCompleteMode="Suggest"
onselectedindexchanged="ddlto_SelectedIndexChanged" />
</td></br>
<asp:CompareValidator ID="cm1" runat="server" Operator="NotEqual" Type="string" ControlToValidate="ddlfrom" ControlToCompare="ddlto" ErrorMessage="The 'Departure City' and 'Destination City' cannot be same. Please re-type." ForeColor="red"
BackColor="yellow" Display="Dynamic" SetFocusOnError="True"> </asp:CompareValidator
It is working properly for that page but when i am clicknig on any other button of that page to redirect to other page again the same messaage of compare validator is printing and i cannot redirect to another page.Means i have 3 pages bus,train and flight when i am removing this compare validator code then i am able to redirext the pages..but when i place these code..in my asp page then, when i click on flight button to redirect to the flight page,it is showing the same message as i have typd in compare validator code.it is not redirecting.PLZZ HELP

You need to add ValidationGroup property to validator and button which should do validation
<asp:CompareValidator ID="ddlto" ... ValidationGroup="MyValidation"... />
<asp:Button ID="MyBtn" ... ValidationGroup="MyValidation"... />
Just make sure, that validator and button have same group.

use vlaidation group property
<asp:CompareValidator ID="cm1" runat="server" Operator="NotEqual" Type="string"
ControlToValidate="ddlfrom" ControlToCompare="ddlto" ErrorMessage="The 'Departure City'
and 'Destination City' cannot be same. Please re-type." ForeColor="red"
BackColor="yellow" Display="Dynamic" SetFocusOnError="True"> </asp:CompareValidator>
vlaidationgroup="abc"
here add this prprety along with other properties and give same to that button also then it will be cleared.

Here is some documentation about the ValidationGroup attribute for Form Elements.
http://msdn.microsoft.com/en-us/library/ms227424(v=vs.100).aspx
The basic idea is to group all the elements you want to be validated when you click a specific button, by identifying them with the same ValidationGroup value

ASP Validators not working?

I feel embarrassed to be posting this as I'm pretty sure I'm missing something really simple, and this certainly isn't the first time I've used asp validators. I have the following validator controls:
<asp:RequiredFieldValidator runat="server" ControlToValidate="txtTitle" EnableClientScript="false" ErrorMessage="*" ValidationGroup="groupUpdateAL" />
<asp:RequiredFieldValidator ID="RequiredFieldValidator2" runat="server" ControlToValidate="txtAbbr" EnableClientScript="false" ErrorMessage="*" ValidationGroup="groupUpdateAL" />
<asp:RequiredFieldValidator ID="RequiredFieldValidator1" runat="server" ControlToValidate="ddlColour" EnableClientScript="false" ValidationGroup="groupUpdateAL" ErrorMessage="*" />
<asp:Button ID="btnSave" runat="server" Text="Save" ValidationGroup="groupUpdateAL" CausesValidation="true" /><br />
For some reason, if leaving the controls empty I am given the following error:
Length cannot be less than zero.
Parameter name: length
It seems the validation controls aren't catching an invalid input.
What I've Tried:
I suspected it may have been client validation intercepting the postback, which is why you can see EnableClientScript is set to false now. Didn't work.

Try testing page validity in the onclick event of your btnSave :
if(Page.IsValid)
{
//Do your stuff
}
else
{
Response.Write("error");
}

Validation is on new screen
in c# file avalilabel on this image plzz click
on this image
enter image description here

Create database to get querystring
Create connection file in visual studio

Custom Validator firing but it does not update the ValidationSummary

Hi I am working on a custom form field validator, it seems like the custom validator is working by not allowing it to continue to the next page, but it doesn't update the Validation Summary nor does it display the asterisk and the labels that i've made visable. I also have other validators like RequiredFieldValidator on the same field. My ValidationGroup is set, as is the Text and IsValid. I even wrote and set a dummy client side validation method in javascript as some workarounds suggests.
here is the validation summary code in asp.net
<asp:ValidationSummary ID="ValidatorSummary" runat="server" ValidationGroup="Step2" />
here is the custom validator and the required field one
<asp:CustomValidator ID="AddressVerification" runat="server" ErrorMessage="Please enter a valid address." Display="Dynamic" ValidationGroup="Step2" OnServerValidate="AddressVerification_ServerValidate" ClientValidationFunction="CustomValidatorDummy" Text="*" Enabled="true" EnableClientScript="true"></asp:CustomValidator>
<asp:RequiredFieldValidator ID="RFValidatorHomeAddress" runat="server" ErrorMessage="Please enter home address." Text="*" Display="Dynamic" ValidationGroup="Step2" ControlToValidate="txtHomeAddress"></asp:RequiredFieldValidator>
here is the custom validation method in the code behind
protected void AddressVerification_ServerValidate(object sender, ServerValidateEventArgs e)
{
//lets just say it doesn't validate and sets the IsValid to false
lblUspsValidatorResHomeCity.Visible = true;
lblUspsValidatorResHomeState.Visible = true;
lblUspsValidatorResHomeZip.Visible = true;
e.IsValid = false;
}
please advise, thanks.
EDIT:
Answered - as bitxwise mentioned. the validation summary should be placed inside an update panel as well. Thanks!
Like so:
<asp:UpdatePanel ID="UpdatePanelValidationSummaryHome" ChildrenAsTriggers="false" UpdateMode="Conditional"
runat="server">
<ContentTemplate>
<asp:ValidationSummary ID="AddressHomeValidationSummary" runat="server" ValidationGroup="AddressHomeValidationGroup"
CssClass="errors" />
</ContentTemplate>
and then calling the update:
UpdatePanelValidationSummaryHome.Update();

You seem to be missing ControlToValidate in your declaration of CustomValidator.
EDIT
If your CustomValidator aggregates multiple controls, then try this:
ASPX
<asp:TextBox ID="txtMyTextBox" runat="server" />
<asp:CustomValidator ID="AddressVerification" runat="server"
Display="Dynamic"
ErrorMessage="Please enter a valid address."
OnServerValidate="AddressVerification_ServerValidate"
Text="*"
ValidationGroup="Step2" />
<asp:RequiredFieldValidator ID="rfvAddress" runat="server"
ControlToValidate="txtMyTextBox"
Display="Dynamic"
ErrorMessage="Please enter an address"
Text="*"
ValidationGroup="Step2" />
...
<asp:ValidationSummary ID="ValidatorSummary" runat="server"
ValidationGroup="Step2" />
...
<asp:Button ID="btnCheckAddresses" runat="server"
CausesValidation="true"
Text="Check Addresses"
ValidationGroup="Step2" />
CS
protected void AddressVerification_ServerValidate(object source, ServerValidateEventArgs args) {
args.IsValid = !string.IsNullOrEmpty(txtMyTextBox.Text) && !txtMyTextBox.Text.Contains(' ');
}
Note that the validation group of the control invoking the post back has CausesValidation="true" and has the same ValidationGroup as the validators.
EDIT 2
If your postback control was in the UpdatePanel but the ValidationSummary was not, then the partial postback would not have refreshed the ValidationSummary. Once you removed the postback control from the UpdatePanel, I imagine it would then generate a full postback, which would refresh your ValidationSummary.
I don't know what else is in your UpdatePanel, but many people report having issues with their validators being in UpdatePanel's.
Check out MSDN,
When you use the ValidationSummary
control inside an UpdatePanel control,
make sure that the validator control
and the control it is associated with
are in the same panel. For more
information about using the
UpdatePanel control for partial-page
updates, see Partial-Page Rendering
Overview.
as well as this MSDN blog.

Make sure every control (textbox, checkbox, etc) that is being validated, every RequiredValidator, CustomValidator and ValidationSummary has the same ValidationGroup value.
ie.
<asp:CustomValidator ID="CustomValidator6" runat="server" ErrorMessage="The field is required"
ValidationGroup="myValGroup">*</asp:CustomValidator>
Of course this will only work if all the controls are inside the same panel or parent control.

In my case the validation summary was not showing because the submit button was in a separate update panel.
<Triggers>
<asp:PostBackTrigger ControlID="ButtonSubmit" />
</Triggers>
Once I added the above code the summary appeared.

problem with asp.net validationcontrol

I have a textbox and I have set required validationcontrol on it on click of a button.
<asp:TextBox runat="server" ID="name" Width="120"></asp:TextBox>
<asp:RequiredFieldValidator ID="rfvname" runat="server" ControlToValidate="name" ErrorMessage="Name is required" Display="Dynamic" />
</td>
but the problem is when I am clicking on modify shared webpart and when I click on APPLY or OK button it is not saving as my form is empty . and I can't put
CausesValidation="false" on that button as this button is by default in sharepoint.
Any idea how to resolve this...?

You can use the ValidationGroup property to group all the Validators and validation fields together.

Yes using the ValidationGroup tag will help to relate the controls in a single form and will tell the submit button which fields are associated. Also make sure you have a ValidationSummary control on the page with the same ValidationGroup value. Also consider adding an InitialValue="" onto the TextBox control.
<asp:ValidationSummary ID="vs1" ShowMessageBox="true" ShowSummary="false" DisplayMode="List" runat="server" ValidationGroup="Form" HeaderText="There were problems with your submission:" />
<asp:TextBox runat="server" ID="name" Width="120"></asp:TextBox>
<asp:RequiredFieldValidator ID="rfvname" ValidationGroup="Form" runat="server" ControlToValidate="name" InitialValue="" ErrorMessage="Name is required" Display="Dynamic" />
<asp:LinkButton ID="lnkSubmit" Text="Submit" OnClick="lnkSubmit_Click" ValidationGroup="Form" runat="server"></asp:LinkButton>