自定义验证客户端忽略无效状态

Question

I want to make custom validator which checks if objects of given name already exists in DB. WS works fine and arg.IsValid is set false BUT when I uncomment Page_ClientValidate(); function goes into infinite loop ( I guess it runs all validators functions that why) nevertheless it return false but when page is submited, validator starts to return true O.o'.

How to abort postback if txtname is not valid? I suspect it because when I press button smsCodeValidator is actually run but aborted due to postback

<asp:CustomValidator 
  ID="cvtxtSMSCode" 
  runat="server" Display="Dynamic" 
  ControlToValidate="txtName" 
  EnableClientScript="true"
  ClientValidationFunction="$U.nameValidator" 
  ForeColor="Red" 
  ErrorMessage="already exists" 
  ValidationGroup="vgName">
</asp:CustomValidator>

nameValidator: function (source, arg) {
    $.ajax({
        type: "POST",
        url: "/../../../../WS/Utility.asmx/NameValidator",
        data: JSON.stringify({ "toTest": arg.Value }),
        contentType: "application/json; charset=utf-8",
        dataType: "json",
        success: function (result) {
            if (result.d == true) {
                arg.IsValid = true;
                $(source).hide();
                return;
            }
            else {
                $(source).show();
                arg.IsValid = false;
                alert(arg.IsValid);
                //Page_ClientValidate();
                return;
            }
        }
    });
},

<asp:Button ID="btnSave" ValidationGroup="vgName" 
runat="server" 
OnClick="btnSaveChanges_Click"
Text="Save" />

Answer 1

I believe you're going into the infinite loop because you're trying to validate the page when you know it's in an invalid state.

Page_ClientValidate() will call each of the validators in turn to make sure they have fired and when it gets to your custom validator you are kicking it off again which will cause the recursion you are seeing. A better option would be to check the value of Page_IsValid instead which is kept up to date by the other validators as well.

Finally, don't forget that if the text box is empty the validator won't be called, you need to have a required field validator on there as well.

More details can be found on the MSDN article: ASP.Net Validation In Depth .