Q: How can I validate the date is not the future date in .net c# Just wandering, how can I validate the date is not the future date in .net c#.
Example:
I have applied a validation there for required field validation. But somehow I have no idea how to apply the validation to check the start date to make sure it's not the future date (date not greater then the current date)?
  <tr>
        <td align="right">Start Date:</td>
        <td><asp:TextBox runat="server" ID="activeDate" size="8"/>(YYYY-MM-DD)
            <asp:RequiredFieldValidator ID="reqvactiveDate" runat="server"
                 ControlToValidate="activeDate" Display="Dynamic" EnableClientScript="true"
                 ErrorMessage="required" />

        </td>
    </tr>

than I wrote the following code to tried out the date validation. The date validation doesn't seem working for me :(
    <tr>
        <td align="right">Start Date:</td>
        <td><asp:TextBox runat="server" ID="activeDate" size="8"/>(YYYY-MM-DD)
            <asp:RequiredFieldValidator ID="reqvactiveDate" runat="server"
                 ControlToValidate="activeDate" Display="Dynamic" EnableClientScript="true"
                 ErrorMessage="required" />

            <asp:CustomValidator runat="server"
                ID="valDateRange" 
                ControlToValidate="activeDate"
                onservervalidate="valDateRange_ServerValidate" 
                ErrorMessage="enter valid date" />
        </td>
    </tr> 

code behind:
   protected void valDateRange_ServerValidate(object source, ServerValidateEventArgs args)
   {
       DateTime minDate = DateTime.Parse("1000/12/28");
       DateTime maxDate = DateTime.Parse("2011/05/26");
       DateTime dt;

       args.IsValid = (DateTime.TryParse(args.Value, out dt)
                       && dt <= maxDate
                       && dt >= minDate);
   }


A: I think you're getting the error for this: DateTime.Parse("1000/12/28") Instead, try DateTime.MinValue. You can also optionally use compareValidators..
Also, any reason you are not just doing [your date] < DateTime.now ?

A: DateTime implements an IComparer interface. Check if its greater than DateTime.Now 
There is no reason to parse it, just do:
if(datetime1>datetime2)
{
    ....
}


A: Here is my code that does the validation of the date value not to be in the future on the  client side:
ASPX code:
<tr>
  <td align="right">
    Start Date:
  </td>
  <td>
    <asp:TextBox runat="server" ID="txtActiveDate" size="8"/>(YYYY-MM-DD)
    <!-- Validate if the entered date value is valid -->
    <asp:CompareValidator ID="cvIsActiveDateValid" runat="server"
     ControlToValidate="txtActiveDate"
     ErrorMessage="Invalid Start Date"
     Operator="DataTypeCheck" 
     Type="Date"></asp:CompareValidator>         
    <!-- Validate if the entered value is not future dated -->
    <asp:CompareValidator ID="cvIsActiveDateNotInFuture" runat="server" 
    ControlToValidate="txtActiveDate" 
    ErrorMessage="Start Date cannot be a future date." 
    Operator="LessThanEqual" 
    Type="Date"></asp:CompareValidator>
  </td>
</tr>

ASPX.CS code:
protected void Page_Load(object sender, EventArgs e)
{
  SetTodaysDateToCompareValidators();
  ...
}

protected void SetTodaysDateToCompareValidators()
{
  string defaultDateFormat = "YYYY-MM-DD";
  string today = DateTime.Today.ToString(defaultDateFormat);
  cvActiveDate.ValueToCompare = today; 
}

