[英]Custom Validation Rule WPF and Items control
在綁定到數據源的ItemsControl
內,我嘗試使用自定義驗證規則來驗證TextBox
,該規則接受參數,以下是驗證規則的代碼。
public class RatioValidation : ValidationRule
{
public override ValidationResult Validate(object value, System.Globalization.CultureInfo cultureInfo)
{
if (!String.IsNullOrEmpty(Maturity.MaturityValue) && Helper.IsDateInCorrectFormat(Maturity.MaturityValue))
{
String strVal = Convert.ToString(value);
Double ratio = 0;
Boolean isValid = Double.TryParse(strVal, out ratio);
if (isValid)
{
if (ratio <= 0)
return new ValidationResult(false, "Please enter a valid ratio!");
else return new ValidationResult(true, null);
}
return new ValidationResult(false, "Please enter a valid ratio!");
}
else return new ValidationResult(true, null);
}
private MaturityDependencyForValidation _maturity;
public MaturityDependencyForValidation Maturity
{
get { return _maturity; }
set { _maturity = value; }
}
}
public class MaturityDependencyForValidation : DependencyObject
{
public String MaturityValue
{
get { return (String)GetValue(MaturityValueProperty); }
set { SetValue(MaturityValueProperty, value); }
}
public static readonly DependencyProperty MaturityValueProperty =
DependencyProperty.Register("MaturityValue", typeof(String), typeof(MaturityDependencyForValidation), new UIPropertyMetadata(null));
}
然后像下面這樣使用它,
<TextBox Grid.Row="1" Grid.Column="2" Name="txtRatio" BorderThickness="0" Width="148" Tag="{Binding StrMaturity, UpdateSourceTrigger=PropertyChanged}">
<TextBox.Text>
<Binding Path="Ratio" Mode="TwoWay" UpdateSourceTrigger="PropertyChanged">
<Binding.ValidationRules>
<leg:RatioValidation ValidatesOnTargetUpdated="True">
<leg:RatioValidation.Maturity>
<leg:MaturityDependencyForValidation MaturityValue="{Binding txtMaturity}"/>
</leg:RatioValidation.Maturity>
</leg:RatioValidation>
</Binding.ValidationRules>
</Binding>
</TextBox.Text>
</TextBox>
在輸出窗口中出現異常:
找不到目標元素的管理FrameworkElement或FrameworkContentElement。 BindingExpression:Path = txtMaturity; DataItem = null; 目標元素是“ MaturityDependencyForValidation”(HashCode = 63478077); 目標屬性為“成熟度”(類型為“字符串”)
在RatioValidation
規則內, Maturity
的值永遠不會從數據綁定中綁定。 我需要此值進行數據綁定。 請幫忙。
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