物业电网项目和DoubleClick [英] Property grid item and DoubleClick
本文介绍了物业电网项目和DoubleClick的处理方法，对大家解决问题具有一定的参考价值，需要的朋友们下面随着小编来一起学习吧！
问题描述
我使用PropertyGrid控件编辑某些对象在我的应用程序。我使用的是自定义类型转换器和TypeEditors为更好的用户界面。
I'm using PropertyGrid control for editing some objects in my application. I'm using custom TypeConverters and TypeEditors for better user interface.
我有问题，自定义类型转换器的布尔属性。如果我有这个类：
I have problem with custom TypeConverter for boolean properties. If I have this class:
public class MyClass {
public string Name { get; set; }
[System.ComponentModel.TypeConverter( typeof( BoolTypeConverter ) )]
public bool Flag { get; set; }
}
和创建实例，并将它设置为SelectedObject在PropertyGrid中 - 一切都很好，直到用户DoubleClicked物业电网项目的形式标志的属性。之后的DoubleClick引发此消息：
and I create instance and set it as SelectedObject in PropertyGrid - all is fine until the user DoubleClicked on property grid item form "Flag" property. After DoubleClick is raised this message:
的类型转换器类如下：
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;
}
}
此行为是非常混乱的用户。我怎样才能prevent呢？
This behaviour is very confusing for users. How can I prevent it?
感谢
推荐答案
您GetStandardValues（）方法是错误的。它必须返回属性的类型，而不是字符串：
Your GetStandardValues() method is wrong. It must return the property type, not strings:
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;
}
这篇关于物业电网项目和DoubleClick的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持IT屋！
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