/// <summary>
/// Modifies the source data before passing it to the target for display in the UI.
/// </summary>
/// <param name="value">The source data being passed to the target.</param>
/// <param name="targetType">The <see cref="T:System.Type" /> of data expected by the target dependency property.</param>
/// <param name="parameter">An optional parameter to be used in the converter logic.</param>
/// <returns>The value to be passed to the target dependency property.</returns>
protected override object Convert(object value, Type targetType, object parameter)
{
bool isNull = value == null;
bool invert = ConverterHelper.ShouldInvert(parameter);
return(invert ? isNull : !isNull);
}
/// <summary>
/// Determines what value this converter should return.
/// </summary>
/// <param name="value">The value produced by the binding source.</param>
/// <param name="targetType">The type of the binding target property.</param>
/// <param name="parameter">The converter parameter to use.</param>
/// <returns>
/// <c>true</c> if the specified value is visible; otherwise, <c>false</c>.
/// </returns>
protected override bool IsVisible(object value, Type targetType, object parameter)
{
bool invert = ConverterHelper.ShouldInvert(parameter);
string stringValue = value as string;
if (invert)
{
return(string.IsNullOrEmpty(stringValue));
}
return(!string.IsNullOrEmpty(stringValue));
}
/// <summary>
/// Determines what value this converter should return.
/// </summary>
/// <param name="value">The value produced by the binding source.</param>
/// <param name="targetType">The type of the binding target property.</param>
/// <param name="parameter">The converter parameter to use.</param>
/// <returns>
/// <c>true</c> if the specified value is visible; otherwise, <c>false</c>.
/// </returns>
protected override bool IsVisible(object value, Type targetType, object parameter)
{
bool invert = ConverterHelper.ShouldInvert(parameter);
return(invert ? (value == null) : (value != null));
}
