Tek-Tips is the largest IT community on the Internet today!
Members share and learn making Tek-Tips Forums the best source of peer-reviewed technical information on the Internet!
-
Congratulations TouchToneTommy on being selected by the Tek-Tips community for having the most helpful posts in the forums last week. Way to Go!
Validator for ListBox
- Thread starter groston
- Start date
It's possible. In this sample, the validator's error message will appear when any of page controls posts back, or during selection on the list box - if all items are unselected.
Code:
<asp:ListBox ID="lb" Runat=server SelectionMode=Multiple>
<asp:ListItem Value="1">Item 1</asp:ListItem>
<asp:ListItem Value="2">Item 2</asp:ListItem>
<asp:ListItem Value="3">Item 3</asp:ListItem>
</asp:ListBox>
<asp:RequiredFieldValidator ID="rvlb" Runat=server ControlToValidate="lb" InitialValue="" ErrorMessage="Select Item" />- Thread starter
- #3
- Thread starter
- #4
You can set the MaxLength property of a TextBox to limit the number of characters entered. If you need to ensure that a specific number of characters is entered, then the best solution would be to use a RegularExpressionValidator or CustomValidator. I'm not an expert in RegEx, but have used CustomValidators.
Code:
<head>
<script language=javascript>
function checkChars(source, arguments){
arguments.IsValid = true;
var len = arguments.Value.length;
// ensure that 5 characters are entered
if(len != 5){
arguments.IsValid = false;
}
}
</script>
</head>
<asp:TextBox ID="myText" Runat=server />
<asp:CustomValidator ID="vldMyText" Runat=server ErrorMessage="Invalid number of characters" ControlToValidate="myText" ClientValidationFunction="checkChars" />- Thread starter
- #6
LV,
Again, thanks for your help. This worked out well, with one exception - when the user hits a 'cancel' button on the page, the validator still fires. I guess I need to figure out how to determine the event that causes a page reload and skip the validation code if the 'cancel' button was hit.
----
Gerry Roston
gerry@pairofdocs.net
Again, thanks for your help. This worked out well, with one exception - when the user hits a 'cancel' button on the page, the validator still fires. I guess I need to figure out how to determine the event that causes a page reload and skip the validation code if the 'cancel' button was hit.
----
Gerry Roston
gerry@pairofdocs.net
- Thread starter
- #8
- Status
Similar threads
