Eigenschaftsrasterelement und DoubleClick

Question

Ich verwende das PropertyGrid-Steuerelement zum Bearbeiten einiger Objekte in meiner Anwendung. Ich verwende benutzerdefinierte TypeConverter und TypeEditors für bessere Benutzeroberfläche.

Ich habe ein Problem mit benutzerdefinierten TypeConverter für boolesche Eigenschaften. Wenn ich diese Klasse haben:

public class MyClass { 
    public string Name { get; set; } 

    [System.ComponentModel.TypeConverter(typeof(BoolTypeConverter))] 
    public bool Flag { get; set; } 
} 

und ich schaffen Instanz und legen Sie es als SelectedObject in Property - alles ist in Ordnung, bis der Benutzer auf Eigenschaft Rasterelement Form „Flag“ Eigenschaft DoubleClicked. Nachdem Doubleclick diese Meldung ausgelöst wird: alt text http://tcks.wz.cz/property_grid_error.PNG

Die Klasse Typeconverter aussieht:

public class BoolTypeConverter : System.ComponentModel.TypeConverter { 
    public const string TEXT_TRUE = "On"; 
    public const string TEXT_FALSE = "Off"; 
    public const string TEXT_NONE = "<none>"; 

    public override object CreateInstance(System.ComponentModel.ITypeDescriptorContext context, System.Collections.IDictionary propertyValues) { 
     object ret = base.CreateInstance(context, propertyValues); 
     return ret; 
    } 
    public override bool GetCreateInstanceSupported(System.ComponentModel.ITypeDescriptorContext context) { 
     bool ret = base.GetCreateInstanceSupported(context); 
     return ret; 
    } 
    public override bool IsValid(System.ComponentModel.ITypeDescriptorContext context, object value) { 
     bool ret; 
     if (value is string) { 
      string tmpValue = value.ToString().Trim(); 

      if (string.Compare(tmpValue, TEXT_NONE, StringComparison.InvariantCultureIgnoreCase) == 0) { 
       ret = true; 
      } 
      else if (string.Compare(tmpValue, TEXT_TRUE, StringComparison.InvariantCultureIgnoreCase) == 0) { 
       ret = true; 
      } 
      else if (string.Compare(tmpValue, TEXT_FALSE, StringComparison.InvariantCultureIgnoreCase) == 0) { 
       ret = true; 
      } 
      else { 
       bool blValue; 
       ret = bool.TryParse(tmpValue, out blValue); 
      } 
     } 
     else { 
      ret = base.IsValid(context, value); 
     } 

     return ret; 
    } 

    public override bool CanConvertFrom(System.ComponentModel.ITypeDescriptorContext context, Type sourceType) { 
     bool ret = false; 
     if (sourceType == typeof(string)) { 
      ret = true; 
     } 
     else { 
      ret = base.CanConvertFrom(context, sourceType); 
     } 

     return ret; 
    } 
    public override object ConvertFrom(System.ComponentModel.ITypeDescriptorContext context, System.Globalization.CultureInfo culture, object value) { 
     object ret = null; 

     bool converted = false; 
     if (value is string) { 
      string tmpValue = value.ToString().Trim(); 
      if (string.Compare(tmpValue, TEXT_NONE, StringComparison.InvariantCultureIgnoreCase) == 0 
       || string.IsNullOrEmpty(tmpValue)) { 
       ret = null; 
       converted = true; 
      } 
      else if (string.Compare(tmpValue, TEXT_TRUE, StringComparison.InvariantCultureIgnoreCase) == 0) { 
       ret = true; 
       converted = true; 
      } 
      else if (string.Compare(tmpValue, TEXT_FALSE, StringComparison.InvariantCultureIgnoreCase) == 0) { 
       ret = false; 
       converted = true; 
      } 
      else { 
       bool blValue; 
       if (converted = bool.TryParse(tmpValue, out blValue)) { 
        ret = blValue; 
       } 
      } 
     } 

     if (false == converted) { 
      ret = base.ConvertFrom(context, culture, value); 
     } 
     return ret; 
    } 

    public override bool CanConvertTo(System.ComponentModel.ITypeDescriptorContext context, Type destinationType) { 
     bool ret = false; 
     if (destinationType == typeof(bool)) { 
      ret = true; 
     } 
     else { 
      ret = base.CanConvertTo(context, destinationType); 
     } 

     return ret; 
    } 
    public override object ConvertTo(System.ComponentModel.ITypeDescriptorContext context, System.Globalization.CultureInfo culture, object value, Type destinationType) { 
     object ret = null; 

     bool converted = false; 
     if (destinationType == typeof(string)) { 
      if (null == value) { 
       ret = TEXT_NONE; 
       converted = true; 
      } 
      else if (value is bool? || value is bool) { 
       if ((bool)value) { ret = TEXT_TRUE; } 
       else { ret = TEXT_FALSE; } 

       converted = true; 
      } 
      else if (value is string) { 
       ret = value; 
       converted = true; 
      } 
     } 
     if (false == converted) { 
      ret = base.ConvertTo(context, culture, value, destinationType); 
     } 
     return ret; 
    } 

    public override StandardValuesCollection GetStandardValues(System.ComponentModel.ITypeDescriptorContext context) { 
     StandardValuesCollection ret; 
     Type tpProperty = context.PropertyDescriptor.PropertyType; 
     if (tpProperty == typeof(bool)) { 
      ret = new StandardValuesCollection(new string[]{ 
      TEXT_TRUE, TEXT_FALSE 
     }); 
     } 
     else if (tpProperty == typeof(bool?)) { 
      ret = new StandardValuesCollection(new string[]{ 
       TEXT_TRUE, TEXT_FALSE, TEXT_NONE 
      }); 
     } 
     else { 
      ret = new StandardValuesCollection(new string[0]); 
     } 

     return ret; 
    } 
    public override bool GetStandardValuesSupported(System.ComponentModel.ITypeDescriptorContext context) { 
     bool ret; 
     Type tpProperty = context.PropertyDescriptor.PropertyType; 
     if (tpProperty == typeof(bool) || tpProperty == typeof(bool?)) { 
      ret = true; 
     } 
     else { 
      ret = false; 
     } 

     return ret; 
    } 
} 

Dieses Verhalten ist für Benutzer sehr verwirrend. Wie kann ich das verhindern?

Dank

Answer 1

Ihre GetStandardValues ​​() Methode ist falsch. Es muss den Eigenschaftstyp, keine Zeichenfolgen zurückgeben:

public override StandardValuesCollection GetStandardValues(ITypeDescriptorContext context) 
{ 
    StandardValuesCollection ret; 
    Type tpProperty = context.PropertyDescriptor.PropertyType; 

    if (tpProperty == typeof(bool)) 
     ret = new StandardValuesCollection(new object[] { true, false }); 
    else if (tpProperty == typeof(bool?)) 
     ret = new StandardValuesCollection(new object[] { true, false, null }); 
    else 
     ret = new StandardValuesCollection(new object[0]); 

    return ret; 
}