CODEWITHSUNDEEP
wpfvalidationrule
barakisbrown
barakisbrown

Reputation: 1323

ValidationRule Red Border Issue

In my WPF Application, I have created ValidationRules for my TextBoxes so that it will not allow an empty string which works fine and shows a red border with text telling the user it can not be empty. When the application launches, all the fields are blank waiting for input but I still see the red border around them. Is this normal behavior? Note: I would prefer it firing after either a propertychange event or lostfocus event fires when the user using the form not when the form initially loads.

Example of the validation I am doing:

 <TextBox x:Name="itemNum" HorizontalAlignment="Left" Height="23" Margin="82,58,0,0"     VerticalAlignment="Top" Width="90"
            HorizontalContentAlignment="Left" VerticalContentAlignment="Center" PreviewKeyDown="ItemNum_PreviewKeyDown" 
            PreviewTextInput="ItemNum_PreviewTextInput" TabIndex="0" Validation.ErrorTemplate="{StaticResource validationErrorTemplate}">
            <TextBox.Text>
                <Binding Path="rxID" Mode="TwoWay" StringFormat="{}{0:#}" UpdateSourceTrigger="PropertyChanged">
                    <Binding.ValidationRules>
                        <MY:TextBoxNotEmptyValidationRule x:Name="rxIDValidation" ValidatesOnTargetUpdated="True" />
                    </Binding.ValidationRules>
                </Binding>
            </TextBox.Text>
        </TextBox>

My TextBoxNotEmptyValidationRule Class:

public override ValidationResult Validate(object value, System.Globalization.CultureInfo cultureInfo)
     {
        string str = value as string;
        if (string.IsNullOrEmpty(str))
        {
            return new ValidationResult(false, "Value CAN NOT BE empty");
        }
        return ValidationResult.ValidResult;
    }

Upvotes: 1

Views: 1099

Answers (2)

adityaswami89
adityaswami89

Reputation: 583

You can look at the following link : Validation on Load

Ideally this is the normal behavior in XAML applications if you use IDataErorInfo or INotifyDataErrorInfo . you can use beginInit and EndInit to achieve your desired output.

Upvotes: 0

TuciBeyin
TuciBeyin

Reputation: 11

According to your logic, it seems that it is normal. Lets define a bool flag and set it false or true, does not matter, than when application is run and check the flag, if flag value is initial value do not do anything. Beside this, you "if" check needs to check also focused element. If focused element is our textbox and your flag is not initial value so you can change the textblock border.

Upvotes: 0

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