如何在属性网格中显示下拉控件? [英] How to show Drop down control in Property Grid?

问题描述

我正在我的项目中添加属性网格控件.我必须在属性网格的一个字段中显示下拉框.有什么解决方案可以应用这个.

I am adding the Property grid control in my project. I have to show the Drop down box in one field of Property Grid. Is there any solution to apply this.

推荐答案

您必须为 PropertyGrid 中的属性声明一个类型编辑器，然后添加到选择列表中.此示例创建一个 类型转换器，然后覆盖 GetStandardValues() 方法为下拉菜单提供选择:

You have to declare a type editor for the property in your PropertyGrid and then add to the list of choices. This example creates a Type Converter and then overrides the GetStandardValues() method to provide choices to the drop-down:

private String _formatString = null;
[Category("Display")]
[DisplayName("Format String")]
[Description("Format string governing display of data values.")]
[DefaultValue("")]
[TypeConverter(typeof(FormatStringConverter))]
public String FormatString { get { return _formatString; } set { _formatString = value; } }

public class FormatStringConverter : StringConverter
{
    public override Boolean GetStandardValuesSupported(ITypeDescriptorContext context) { return true; }
    public override Boolean GetStandardValuesExclusive(ITypeDescriptorContext context) { return true; }
    public override TypeConverter.StandardValuesCollection GetStandardValues(ITypeDescriptorContext context)
    {
        List<String> list = new List<String>();
        list.Add("");                      
        list.Add("Currency");              
        list.Add("Scientific Notation");   
        list.Add("General Number");        
        list.Add("Number");                
        list.Add("Percent");               
        list.Add("Time");
        list.Add("Date");
        return new StandardValuesCollection(list);
    }
}

关键是在行中分配了类型转换器的属性:

The key is the property being assigned a Type Converter in the line:

[TypeConverter(typeof(FormatStringConverter))]

这让您有机会通过覆盖来介绍自己的行为.

That provides you with the opportunity to introduce your own behavior via overrides.

这是一个更简单的示例，它允许属性的 Enum 类型自动将其值提供给 PropertyGrid 下拉列表:

Here's a simpler example, which allows the Enum type of a Property to automatically provide its values to the PropertyGrid drop-down:

public enum SummaryOptions
{
    Sum = 1,
    Avg,
    Max,
    Min,
    Count,
    Formula,
    GMean,
    StdDev
}

private SummaryOptions _sumType = SummaryOptions.Sum;
[Category("Summary Values Type")]
[DisplayName("Summary Type")]
[Description("The summary option to be used in calculating each value.")]
[DefaultValue(SummaryOptions.Sum)]
public SummaryOptions SumType { get { return _sumType; } set { _sumType = value; } }

由于该属性是 Enum 类型，因此这些 enum 值会自动传递成为下拉选项.

By virtue of the fact that the property is an Enum type, those enum values pass through to become the drop-down options automatically.

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