CODEWITHSUNDEEP
c#winformspropertiesattributesembedded-resource
Joshua W
Joshua W

Reputation: 1133

Attribute in C# winforms to specify resource selector?

I made a custom control for WinForms in C#. One of it's properties is an audio stream that will be played at some point. Is there a way I can tell VS that this property should be chosen from the resource manifest (specifically audio resources) with a property or similar?

The property, defined.

The commented property is an audio stream.

Control properties.

This is how it shows in the WinForms designer.

Binary data editor.

This is what you get when you click the edit [...] button. I want this to be replaced by an [audio] resource chooser.

Upvotes: 2

Views: 700

Answers (2)

J.Hudler
J.Hudler

Reputation: 1258

I'm posting a code below that shows how I would do it myself.

Just some observations:

  • In my code, I created a String property AudioName which will be set in the designer. This property refers to the resource name in your assembly. The Audio (read-only) property of type Stream you are interested in, will then be retrieved from the chosen resource name.

  • As Marc-André Jutras pointed in his answer, you'll need to code your own UITypeEditor or TypeConverter to retrieve the Audio resources from your assembly. I've chosen in this case to implement a custom TypeConverter.

    Public Class Form1
    <System.ComponentModel.TypeConverter(GetType(AudioConverter)), System.ComponentModel.DefaultValue("(none)")>
    Public Property AudioName As String

    <System.ComponentModel.Browsable(False)> 'This will make the property not appear in the designer
    Public ReadOnly Property Audio As Stream
        Get
            If String.IsNullOrWhiteSpace(AudioName) OrElse
                AudioName = "(none)" Then
                Return Nothing
            End If
            Try
                Return My.Resources.ResourceManager.GetStream(AudioName)
            Catch ex As Exception
                Return Nothing
            End Try
        End Get
    End Property
End Class

Public Class AudioConverter
    Inherits System.ComponentModel.TypeConverter

    Public Overrides Function GetStandardValuesSupported(context As System.ComponentModel.ITypeDescriptorContext) As Boolean
        Return True
    End Function

    ' Set the property to be informed only from predefined (standard) values
    Public Overrides Function GetStandardValuesExclusive(context As System.ComponentModel.ITypeDescriptorContext) As Boolean
        Return True
    End Function

    ' Get possible values that will be inserted in the drop-down list
    Public Overrides Function GetStandardValues(context As System.ComponentModel.ITypeDescriptorContext) As System.ComponentModel.TypeConverter.StandardValuesCollection

        Dim returnList As New System.Collections.Generic.List(Of String)
        returnList.Add("(none)")
        For Each resItem As System.Collections.DictionaryEntry In My.Resources.ResourceManager.GetResourceSet(System.Globalization.CultureInfo.InvariantCulture, True, False)
            Dim resourceEntry As String = resItem.Key
            If TypeOf resourceEntry Is String Then
                returnList.Add(resourceEntry)
            End If
        Next

        Return New System.ComponentModel.TypeConverter.StandardValuesCollection(returnList)
    End Function
End Class

Upvotes: 0

LightStriker
LightStriker

Reputation: 21024

What you are looking for is:

[Editor(typeof(MyAudioEditor), typeof(UITypeEditor)]

This attribute let you specify a specific editor to be used when that property is displayed in a property grid.

You can then derive and create your new editor from a base type. The base type must be or must derive from System.Drawing.Design.UITypeEditor.

In most case, when the Editor is invoked, you pop-up a form of your choice, and bind its return value to your property.

UITypeEditor has 4 virtual methods and one virtual property that let you change all the behavior when someone interact with your property or when your property is painted in the grid.

Upvotes: 1

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