ConfigurationPropertyAttribute.IsKey Property    
Definition
Important
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Gets or sets a value indicating whether this is a key property for the decorated element property.
public:
 property bool IsKey { bool get(); void set(bool value); };public bool IsKey { get; set; }member this.IsKey : bool with get, setPublic Property IsKey As BooleanProperty Value
true if the property is a key property for an element of the collection; otherwise, false. The default is false.
Examples
The following example shows how to use the IsKey property.
[ConfigurationProperty("name", DefaultValue = "Contoso",
    IsRequired = true, IsKey = true)]
public string Name
{
    get
    {
        return (string)this["name"];
    }
    set
    {
        this["name"] = value;
    }
}
<ConfigurationProperty("name", DefaultValue:="Contoso", IsRequired:=True, IsKey:=True)>
Public Property Name() As String
    Get
        Return CStr(Me("name"))
    End Get
    Set(ByVal value As String)
        Me("name") = value
    End Set
End Property
Remarks
The IsKey property applies only if the property you decorate is a collection. It does not have any effect if the property is not a collection. Multiple elements can be marked as IsKey.