GridViewComboBoxColumn设置DataTypeConverter

GridView中的GridViewComboBoxColumn列，如果需要使用TypeConverter将非字符串类型的数据源转换为字符串进行展示，可按如下几步进行：

例如，数据源为如下枚举类型：

public enum MyColor
{
    Red,
    Yellow,
    Green
}

1. 展示的时候，需要转换为汉字，先定义如下类型，作为GridViewComboBoxColumn的数据源：

public class MyColorItem
{
    public MyColor Value { get; set; }
    
    public string Description { get; set; }
}

2. 创建转换器：

public class MyColorToStringConverter : TypeConverter
{
    public override bool CanConvertFrom(ITypeDescriptorContext context, Type sourceType)
    {
        if(sourceType == typeof(string))
            return true;

        return base.CanConvertFrom(context, sourceType);
    }

    public override object ConvertFrom(ITypeDescriptorContext context, CultureInfo culture, object value)
    {
        if (value is string color)
        {
            switch (color)
            {
                case "红":
                    return MyColor.Red;
                case "黄":
                    return MyColor.Yellow;
                case "绿":
                    return MyColor.Green;
                default:
                    break;
            }
        }

        return base.ConvertFrom(context, culture, value);
    }

    public override bool CanConvertTo(ITypeDescriptorContext context, Type destinationType)
    {
        if (destinationType == typeof(string))
            return true;

        return base.CanConvertTo(context, destinationType);
    }

    public override object ConvertTo(ITypeDescriptorContext context, CultureInfo culture, object value, Type destinationType)
    {
        if (value is MyColor color)
        {
            switch (color)
            {
                case MyColor.Red:
                    return "红";
                case MyColor.Yellow:
                    return "黄";
                case MyColor.Green:
                    return "绿";
                default:
                    break;
            }
        }

        return base.ConvertTo(context, culture, value, destinationType);
    }
}

3. 初始化时设置GridViewComboBoxColumn列的相关属性：

List<MyColorItem> MyColorItemSource = new List<CheckTypeItem>
{
    new MyColorItem{ Value = MyColor.Red, Description = "红" },
    new MyColorItem{ Value = MyColor.Yellow Description = "黄" },
    new MyColorItem{ Value = MyColor.Green, Description = "绿" }
};

var column = radGridView.Columns["MyColor"] as GridViewComboBoxColumn;
if (column != null)
{
    column.DataSource = MyColorItemSource;
    column.ValueMember = "Value";
    column.DisplayMember = "Description";
    column.DataTypeConverter = new MyColorToStringConverter();
}

需要注意的是，如果不定义步骤1中的MyColorItem类型，直接使用List<string>{"红", "黄", "绿"}作为GridViewComboBoxColumn列的DataSource，转换器会报错。