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Sheo Narayan


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asp:RequiredFieldValidator control
RequiredFieldValidator validator control is used to make a field as mandatory in the form.
RequiredFieldValidator validator control is used to make a field as mandatory in the form. Without filling the field user can't submit the form.


Following are some basic properties of all Validator controls
ControlToValidate Gets or sets the input control to validate (eg. The ID value of asp:TextBox control).
Display Dynamic/Static. Used to indicate how the area of error message will be allocated.
Dynamic: Error message area will only be allocated when error will be displayed. Static: Error messagea area will be allocated in either case.
Enabled true/false. Gets or sets whether to enable the validation control or not.
ErrorMessage Gets or sets the text of the error message that will be displayed when validation fails (This is displayed when ValidationSummary validatoin control is used.).
Text Gets or sets the description of the error message text.
ValidationGroup Gets or sets the validation group it belongs to. This is used to group a set of controls.
SetFocusOnError true/false. Used to move focus on the control that fails the validation.
DEMO : RequiredFieldValidator Show Source Code

    <asp:Label ID="lbl" AssociatedControlID="TextBox1" runat="Server" Text="Write into TextBox"></asp:Label>
    <asp:TextBox ID="TextBox1" runat="Server"></asp:TextBox>
    <asp:RequiredFieldValidator ID="req1" runat="Server" ControlToValidate="TextBox1" ErrorMessage="TextBox is Mandatory field" Text="Please write something in the Box."></asp:RequiredFieldValidator>
    <asp:Button ID="btnSubmit" runat="Server" OnClick="ChangeLabelText" Text="Change Label Text" />                
    <asp:ValidationSummary ID="ValidationSummary" runat="Server" ShowMessageBox="true" />