打开 OpenFileDialog 以更改 PropertyGrid 控件中的属性值？

Question

在 Windows 窗体中，我在 PropertyGid 控件中表示一个自定义类，它具有各种字符串属性，如下图所示：

问题是我对当前更改字符串属性值的行为并不完全满意。对于那些需要文件或目录路径的属性，例如“目标”或“工作目录”属性，我想知道实现一个 TypeConverter / Type Descriptor 是否可行且可行，它会在单击时打开 OpenFileDialog在属性网格中字段右侧的向下箭头中。即通过OpenFileDialog选择文件或文件夹，而不是直接在属性网格中写入路径，但如果我想这样做仍然让选项直接写入路径。

也许 .NET Framework 类库已经提供了我请求的 TypeConverter / TypeDescriptor？。如果没有，这可能吗？以及如何开始这样做？

或者任何其他能够打开OpenFileDialog 以更改PropertyGrid 控件中特定属性的值的想法？

Answer 1

有内置的FileNameEditor 和FolderNameEditor UI 类型编辑器可以让您选择文件名和文件夹名，例如：

using System.ComponentModel;
using System.Drawing.Design;
using System.Windows.Forms;
using System.Windows.Forms.Design;
public class MyClass
{
    [Editor(typeof(FileNameEditor), typeof(UITypeEditor))]
    public string FilePath { get; set; }

    [Editor(typeof(FolderNameEditor), typeof(UITypeEditor))]
    public string FolderPath { get; set; }
}

如果您想自定义 FileNameEditor 以仅显示 txt 文件，您可以覆盖其 InitializeDialog 方法：

public class MyFileNameEditor : FileNameEditor
{
    protected override void InitializeDialog(OpenFileDialog openFileDialog)
    {
        base.InitializeDialog(openFileDialog);
        openFileDialog.Filter = "text files (*.txt)|*.txt";
    }
}

Answer 2

在我的应用程序中，我有一个采用图标文件路径的属性、另一个可以采用文件或文件夹的属性，以及其他采用文件夹路径的属性。

因此，我必须为这些属性中的每一个编写变体...

最简单的一种，如果你对FolderBrowserDialog的外观和限制感到满意，那就直接在EditorAttribute类中指定System.Windows.Forms.Design.FolderNameEditor类。否则，Ooki.Dialogs 是一个很好的开源库，可作为获得现代外观对话框的替代方案。

第二个最简单的是选择图标文件路径的编辑器：

''' <summary>
''' Provides a user interface for selecting a icon file name.
''' </summary>
''' <seealso cref="FileNameEditor"/>
Friend Class IconFileNameEditor : Inherits FileNameEditor

#Region " Constructors "

    ''' <summary>
    ''' Initializes a new instance of the <see cref="IconFileNameEditor"/> class.
    ''' </summary>
    Public Sub New()
        MyBase.New()
    End Sub

#End Region

#Region " Private Methods "

    ''' <summary>
    ''' Initializes the open file dialog when it is created.
    ''' </summary>
    ''' <param name="ofd">
    ''' The <see cref="OpenFileDialog"/> to use to select a file name.
    ''' </param>
    Protected Overrides Sub InitializeDialog(ByVal dlg As OpenFileDialog)
        MyBase.InitializeDialog(dlg)

        With dlg
            .Multiselect = False
            .RestoreDirectory = True
            .DereferenceLinks = True
            .Filter = "Icon Files (*.ico;*.icl;*.exe;*.dll)|*.ico;*.icl;*.exe;*.dll|Icons|*.ico|Libraries|*.dll|Programs|*.exe"
            .FilterIndex = 1
            .SupportMultiDottedExtensions = True
        End With
    End Sub

#End Region

End Class

为了选择文件路径或文件夹路径，并寻找已经完成的开源项目以避免向我的项目添加外部依赖项，我采用了 this 文章中提供的自定义 FileFolderDialog 类，并且我设法编写了这样的编辑器：

''' <summary>
''' Provides a user interface for selecting a file or folder name.
''' </summary>
''' <seealso cref="UITypeEditor"/>
Public Class FileOrFolderNameEditor : Inherits UITypeEditor

#Region " Constructors "

    ''' <summary>
    ''' Initializes a new instance of the <see cref="FileOrFolderNameEditor"/> class.
    ''' </summary>
    Public Sub New()
        MyBase.New()
    End Sub

#End Region

#Region " Public Methods"

    ''' <summary>
    ''' Gets the editor style used by the <see cref="UITypeEditor.EditValue(IServiceProvider, Object)"/> method.
    ''' </summary>
    ''' <param name="context">
    ''' An <see cref="ITypeDescriptorContext"/> that can be used to gain additional context information.
    ''' </param>
    ''' <returns>
    ''' A <see cref="UITypeEditorEditStyle"/> value that indicates the style of editor used 
    ''' by the <see cref="UITypeEditor.EditValue(IServiceProvider, Object)"/> method. 
    ''' <para></para>
    ''' If the <see cref="UITypeEditor"/> does not support this method, 
    ''' then <see cref="UITypeEditor.GetEditStyle"/> will return <see cref="UITypeEditorEditStyle.None"/>.
    ''' </returns>
    Public Overrides Function GetEditStyle(ByVal context As ITypeDescriptorContext) As UITypeEditorEditStyle
        Return UITypeEditorEditStyle.Modal
    End Function

    ''' <summary>
    ''' Edits the specified object's value using the editor style indicated by the <see cref="UITypeEditor.GetEditStyle"/> method.
    ''' </summary>
    ''' <param name="context">
    ''' An <see cref="ITypeDescriptorContext"/> that can be used to gain additional context information.
    ''' </param>
    ''' <param name="provider">
    ''' An <see cref="IServiceProvider"/> that this editor can use to obtain services.
    ''' </param>
    ''' <param name="value">
    ''' The object to edit.
    ''' </param>
    ''' <returns>
    ''' The new value of the object. 
    ''' <para></para>
    ''' If the value of the object has not changed, this should return the same object it was passed.
    ''' </returns>
    Public Overrides Function EditValue(ByVal context As ITypeDescriptorContext, ByVal provider As IServiceProvider, ByVal value As Object) As Object

        Using dlg As New OpenFileOrFolderDialog()
            If (dlg.ShowDialog = DialogResult.OK) Then
                Return dlg.SelectedPath
            End If
        End Using

        Return MyBase.EditValue(context, provider, value)

    End Function

#End Region

End Class

这很容易。