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Show ValidationErrors in Validation Summary only in asp.net

<asp:ValidationSummary ID="vsArea" runat="server" />
<div class="controls">
<asp:DropDownList ID="ddlDegreeLevel" runat="server"
placeholder="DegreeLevel" CssClass="form-control">
</asp:DropDownList>
<asp:RequiredFieldValidator ID="rfvDegreeLevel" runat="server"
ControlToValidate="ddlDegreeLevel"
Display="None" ForeColor="Red" InitialValue="-1"
ErrorMessage="Please select degree level" Text="">
</asp:RequiredFieldValidator>
</div>
Errormessage of "rfvDegreeLevel" is show on validation-Summary and also below the control. I also set Display="None" but still show on both area .
I want to show message only on Validation summary.

This is by design...message will be shown in validation control and in the summary. Basically you have 2 options
Show separate messages in your control and validation summary. E.g. you can put a red * in the validation control and detailed error message in the summary, which is a best practice. To achieve this, set both Text and ErrorMessage property of the validation control. Text will be appearing in the control and ErrorMessage will be appearing in the summary.
hide the message from control, set the Display property of the control to none..
You have to add validationgroup to all the controls. For this you can use the following code:
<asp:ValidationSummary ID="vsArea" runat="server" ValidationGroup="degree" />
<div class="controls">
<asp:DropDownList ID="ddlDegreeLevel" runat="server"
placeholder="DegreeLevel" CssClass="form-control">
</asp:DropDownList>
<asp:RequiredFieldValidator ID="rfvDegreeLevel" runat="server"
ValidationGroup="degree"
ControlToValidate="ddlDegreeLevel"
Display="None" ForeColor="Red" InitialValue="-1"
ErrorMessage="Please select degree level" Text="">
</asp:RequiredFieldValidator>
</div>

Required Field Validator always shows the error message

I have this code:
<asp:TextBox ID="txtFirstName" runat="server"></asp:TextBox>
<asp:RequiredFieldValidator ID="rvFirstName" runat="server"
ErrorMessage="Enter First Name"
ForeColor="Red" ControlToValidate="txtFirstName"
SetFocusOnError="True"></asp:RequiredFieldValidator>
The problem is that the error message shows every time the page loads not only after the submit button has been clicked. I want it to show it only if the user tries click the "Next"(submit) button (how it should work).
If this is relevant: The code above is placed in a UserControl which is included in another UserControl(the "Next" button is here) which is then included in a View of a MultiView.
Any ideas

use causeValidation to false on other buttons.
and display to dynamic.
Display="Dynamic" on require filed validator
<asp:RequiredFieldValidator ID="rvFirstName" runat="server" Display="Dynamic"
ErrorMessage="Enter First Name" ForeColor="Red"
ControlToValidate="txtFirstName" SetFocusOnError="True">
</asp:RequiredFieldValidator>

The best way is set ValidationGroup on Button and RequiredFieldValidator.

please take a look on references below, is it you have something like Page.Isvalid in your page?
References : Required Field Validator, displaying on initial page load

<asp:ValidationSummary ID="ValidationSummary1" runat="server"
ShowMessageBox="True" DisplayMode="BulletList"
HeaderText="Validation issues" ShowSummary="False" ValidationGroup="Validation"/>
<asp:TextBox ID="txtFirstName" runat="server"></asp:TextBox>
<asp:RequiredFieldValidator ID="rvFirstName" runat="server" ErrorMessage="Enter First Name" ForeColor="Red" ControlToValidate="txtFirstName" SetFocusOnError="True" ValidationGroup="Validation"></asp:RequiredFieldValidator>
Add the above code and modify your Required Field Validator

Set 'ValidationGroup' for RequiredFieldValidator and the Next button

Remove the SetFocusOnError="True" and add display="Dynamic" instead of SetFocusOnError="True" in your requiredfieldvalidation and set casevalidtion="false" in your page.

01.If you want to display message in page load. protected void Page_Load(object sender, EventArgs e)
{
if (!Page.IsPostBack)
{
Page.Validate();
}
}
Display="Dynamic"

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

ValidationSummary not working when ValidationGroup is specified

I have a few section in an ASP.NET page and need to validate them separately.
Each section has it's own validation summary section so I thought of using the ValidationSummary tag with the ValidationGroup attribute but it does not work.
The following code works but validates all controls in the page:
<asp:TextBox ID="field1" runat="server" TabIndex="1" MaxLength="20" />
<asp:RequiredFieldValidator ID="field1RequiredValidator" ControlToValidate="field1" runat="server"
Display="None" ErrorMessage="mandatory 1" />
<asp:TextBox ID="field2" runat="server" TabIndex="2" MaxLength="20" />
<asp:RequiredFieldValidator ID="field2RequiredValidator" ControlToValidate="field2" runat="server"
Display="None" ErrorMessage="mandatory 2" />
....
<asp:ValidationSummary ID="validationSummary" HeaderText="Sumary" runat="server" />
While the following does not work (no validation whatsoever, on submit I just go to the next page in the wizard):
<asp:TextBox ID="field1" runat="server" TabIndex="1" MaxLength="20" />
<asp:RequiredFieldValidator ID="field1RequiredValidator" ControlToValidate="field1" runat="server"
Display="None" ErrorMessage="mandatory 1" ValidationGroup="xxxx" />
<asp:TextBox ID="field2" runat="server" TabIndex="2" MaxLength="20" />
<asp:RequiredFieldValidator ID="field2RequiredValidator" ControlToValidate="field2" runat="server"
Display="None" ErrorMessage="mandatory 2" ValidationGroup="xxxx" />
....
<asp:ValidationSummary ID="validationSummary" HeaderText="Sumary" runat="server" ValidationGroup="xxxx" />
What am I missing here? Is there extra setup needed or something else?

The default behaviour in ASP.NET is that when the user clicks a button that has no ValidationGroup specified (and has CausesValidation set to true), all validation controls that do not belong to a validation group are validated.
Therefore, to validate a specific group, you need to set the ValidationGroup property of the button that should cause the validation (and also possibly the CausesValidation property).
See the MSDN documentation for Button.ValidationGroup for details and an example.
EDIT: If you need to validate ALL groups on the page, the easiest way is of course to not use validation groups at all. If you however want to validate only some (but more than one) groups, you can do it on the server (in the click handler of the button) by calling:
Validate("groupOne");
Validate("groupTwo");
// ...
Note that this won't trigger client-side validation. See for example this post for a discussion about triggering multiple validation groups on a single button click.
EDIT: I found a blog post describing how to build a reusable "multiple validation group button" for ASP.NET, complete with code. Haven't tried it, but it looks promising.

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>