Add multiple Property Metadata to a Dependency Property in a Workflow Activity

问题

I am building a number of Custom Activities in Windows Workflow and I need to add a DependencyProperty which can list a number of values for that property which the user can then select when using the activity.

e.g. True or False.

I know how to simply pass a default using the PropertyMetadata, and presume that I will have to pass a list/class now the PropertyMetadata?

Has anyone already got an example of how to do this please?

(Example Code below)

public static DependencyProperty TestProperty = DependencyProperty.Register("Test", typeof(string), typeof(CheckActivity), new PropertyMetadata("True"));
/// <summary>
/// Dependency property for 'TestProperty'
/// </summary>   
[DescriptionAttribute("Whether a True/False entry is required")]
[CategoryAttribute("Settings")]
[BrowsableAttribute(true)]
[DesignerSerializationVisibilityAttribute(DesignerSerializationVisibility.Visible)]
public string Type
{
    get
    {
        return ((string)(base.GetValue(CheckActivity.TestProperty)));
    }
    set
    {
        base.SetValue(CheckActivity.TestProperty, value);
    }
}

回答1:

First of all the True/False example isn't great, in that case use a bool type.

For a multi-value item why not use an Enum:-

 public enum ItemEnum
 {
    First,
    Second,
    Third
 }

Now in your Activity:-

 public static DependencyProperty TestProperty = DependencyProperty.Register("Test",  
   typeof(ItemEnum), typeof(TestActivity), new PropertyMetadata(ItemEnum.First));

[Description("Select Item value")]
[Category("Settings")]
[DefaultValue(ItemEnum.First)]
public ItemEnum Type
{
  get
  {
    return (ItemEnum)GetValue(TestActivity.TestProperty);
  }
  set
  {
    SetValue(TestActivity.TestProperty, value);
  }
}

Note the simplification of the Attributes on the property. In particular Browseable being true and DesignerSerializationVisiblity being Visible are defaults so remove them. Also the property grid is easier for the "user" to use if the DefaultValue is defined. Note also dropped the "Attribute" suffix, makes it much more straightforward to read.

来源：https://stackoverflow.com/questions/1728356/add-multiple-property-metadata-to-a-dependency-property-in-a-workflow-activity

标签

workflow

workflow-foundation

dependency-properties

workflow-activity