Validator

in namespace DotVVM.Framework.Controls

Displays the asterisk or validation message for a specified field.

Usage & Scenarios

Displays the asterisk or validation message for a specified field.

Look at the Validation tutorial to see how the validation works.

Sample 1: Basic Validator

The Value property specifies which property will be validated. In the viewmodel, the Text property has the [Required] attribute.

The content inside the Validator control will be displayed when the field is not valid.

page.dothtml
ViewModel.cs

<p>
  <dot:TextBox Text="{value: Text}" />
  <dot:Validator Value="{value: Text}">This field is required!</dot:Validator>
</p>
<dot:Button Text="SEND" Click="{command: Send()}" />

using System.ComponentModel.DataAnnotations;

namespace DotvvmWeb.Views.Docs.Controls.builtin.ValidationMessage.sample1
{
    public class ViewModel
    {
        
        [Required]
        public string Text { get; set; }

        public void Send()
        {
            // do the job
        }
    }
}

Sample 2: CSS Classes for Invalid Values

The Validator has a property InvalidCssClass. If the field is not valid, the Validator control will get this CSS class.

You can also apply the Validator properties to other elements.

page.dothtml
ViewModel.cs

<p>
  <dot:TextBox Text="{value: Text}" />
  
  <dot:Validator Value="{value: Text}" 
                 InvalidCssClass="validation-error">
	*
  </dot:Validator>
</p>

<div Validator.InvalidCssClass="validation-error-row"
     Validator.Value="{value: Text2}"
     style="padding: 10px; width: 200px">
  <dot:TextBox Text="{value: Text2}" />
</div>

<dot:Button Text="SEND" Click="{command: Send()}" />

using System.ComponentModel.DataAnnotations;

namespace DotvvmWeb.Views.Docs.Controls.builtin.ValidationMessage.sample2
{
    public class ViewModel
    {

        [Required]
        public string Text { get; set; }

        [Required]
        public string Text2 { get; set; }


        public void Send()
        {
            // do the job
        }
    }
}

Sample 3: Error Message Texts

There are the ShowErrorMessageText and SetToolTipText properties. If they are set, the error message generated by the [Required] attribute will be displayed in the Validator control or set as a tool tip text.

page.dothtml
ViewModel.cs

<p>
  <dot:TextBox Text="{value: Text}" />
  <dot:Validator Value="{value: Text}" 
                 ShowErrorMessageText="true"/>
</p>

<div Validator.Value="{value: Text2}"
     Validator.SetToolTipText="true">
  <dot:TextBox Text="{value: Text2}" />
</div>

<dot:Button Text="SEND" Click="{command: Send()}" />

using System.ComponentModel.DataAnnotations;

namespace DotvvmWeb.Views.Docs.Controls.builtin.ValidationMessage.sample3
{
    public class ViewModel
    {

        [Required]
        public string Text { get; set; }

        [Required]
        public string Text2 { get; set; }


        public void Send()
        {
            // do the job
        }
    }
}

Show all inherited properties

Properties

Name	Type	Description	Notes	Default Value
ClientIDMode	ClientIDMode	Gets or sets the client ID generation algorithm.	attribute inner element static value bindable default	Static
DataContext	Object	Gets or sets a data context for the control and its children. All value and command bindings are evaluated in context of this value. The DataContext is null in client-side templates.	attribute inner element static value bindable default	null
HideWhenValid	Boolean	Gets or sets whether the control should be hidden even for valid values.	attribute inner element static value bindable default	False
ID	String	Gets or sets the control client ID within its naming container.	attribute inner element static value bindable default	null
IncludeInPage	Boolean	Gets or sets whether the control is included in the DOM of the page.	attribute inner element static value bindable default	True
InnerText	String	Gets or sets the inner text of the HTML element. Note that this property can only be used on HtmlGenericControl directly and when the control does not have any children.	attribute inner element static value bindable default	null
InvalidCssClass	String	Gets or sets the name of CSS class which is applied to the control when it is not valid.	attribute inner element static value bindable default	null
SetToolTipText	Boolean	Gets or sets whether the title attribute should be set to the error message.	attribute inner element static value bindable default	False
ShowErrorMessageText	Boolean	Gets or sets whether the error message text should be displayed.	attribute inner element static value bindable default	False
Value	Object	Gets or sets a binding that points to the validated value.	attribute inner element static value bindable default	null
Visible	Boolean	Gets or sets whether the control is visible. When set to false, `style="display: none"` will be added to this control.	attribute inner element static value bindable default	True

HTML produced by the control

If the Validator control is used as a stand-alone control, it renders a <span>.

<span data-bind="..."></span>

If the properties of Validator are used on another element, it only renders a data-bind attribute.

data-bind="..."

Edit on Github