在 UserControl 中单击属性时错误打开 "Edit Columns"

Question

VB.Net

我有一个带 Dgv1(DataGridView) 的用户控件

我想使用 "Edit Columns" 表单编辑设计中的列

代码用户控件：

Public Class MyUserControl
    Inherits UserControl


    <Editor(GetType(MyColumnEditor), GetType(UITypeEditor))> _
    <DesignerSerializationVisibility(DesignerSerializationVisibility.Content)> _
    Public ReadOnly Property Columns() As DataGridViewColumnCollection
        Get
            Return Me.Dgv1.Columns

        End Get
    End Property


End Class

我的列编辑器：

Public Class MyColumnEditor
    Inherits System.Drawing.Design.UITypeEditor

    Public Overrides Function GetEditStyle(context As ITypeDescriptorContext) As UITypeEditorEditStyle
        Return UITypeEditorEditStyle.Modal
    End Function

    Public Overloads Overrides Function EditValue(context As ITypeDescriptorContext, provider As IServiceProvider, value As Object) As Object

        Dim field As Object = context.Instance.[GetType]().GetField("Dgv1", System.Reflection.BindingFlags.NonPublic Or System.Reflection.BindingFlags.Instance)

        Dim dataGridView1 = CType(field.GetValue(context.Instance), DataGridView)
        dataGridView1.Site = CType(context.Instance, Control).Site
        Dim columnsProperty As Object = TypeDescriptor.GetProperties(dataGridView1)("Columns")
        Dim tdc As Object = New TypeDescriptionContext(dataGridView1, columnsProperty)
        Dim editor = CType(columnsProperty.GetEditor(GetType(UITypeEditor)), UITypeEditor)
        Dim result As Object = editor.EditValue(tdc, provider, value)
        dataGridView1.Site = Nothing
        Return result

    End Function
End Class

TypeDescriptionContext:

Public Class TypeDescriptionContext
    Implements ITypeDescriptorContext

    Public editingObject As Control
    Public editingProperty As PropertyDescriptor
    Public Sub New(obj As Control, property1 As PropertyDescriptor)
        editingObject = obj
        editingProperty = property1
    End Sub

    Public ReadOnly Property Container As IContainer Implements ITypeDescriptorContext.Container
        Get
            Return editingObject.Container
        End Get
    End Property

    Public ReadOnly Property Instance As Object Implements ITypeDescriptorContext.Instance
        Get
            Return editingObject

        End Get
    End Property

    Public Sub OnComponentChanged() Implements ITypeDescriptorContext.OnComponentChanged

    End Sub

    Public Function OnComponentChanging() As Boolean Implements ITypeDescriptorContext.OnComponentChanging
        Return True

    End Function

    Public ReadOnly Property PropertyDescriptor As PropertyDescriptor Implements ITypeDescriptorContext.PropertyDescriptor
        Get
            Return editingProperty
        End Get
    End Property

    Public Function GetService(serviceType As Type) As Object Implements IServiceProvider.GetService
        Return editingObject.Site.GetService(serviceType)
    End Function
End Class

但是当单击列属性进行编辑时显示错误：未设置对象变量或 With 块变量。

https://i.stack.imgur.com/rkeua.jpg

和

同样的代码在C#:中，运行正常

用户控件：

public partial class MyUserControl : UserControl
    {
        public MyUserControl()
        {
            InitializeComponent();
        }

        [Editor(typeof(MyColumnEditor), typeof(UITypeEditor))]
        [DesignerSerializationVisibility(DesignerSerializationVisibility.Content)]
        public DataGridViewColumnCollection Columns
        {
            get { return this.Dgv1.Columns; }
        }
    }

我的列编辑器：

public class MyColumnEditor : UITypeEditor
    {
        public override UITypeEditorEditStyle GetEditStyle(ITypeDescriptorContext context)
        {
            return UITypeEditorEditStyle.Modal;
        }
        public override object EditValue(ITypeDescriptorContext context,
                                         IServiceProvider provider, object value)
        {
            var field = context.Instance.GetType().GetField("Dgv1",
                           System.Reflection.BindingFlags.NonPublic |
                           System.Reflection.BindingFlags.Instance);

            var dataGridView1 = (DataGridView)field.GetValue(context.Instance);
            dataGridView1.Site = ((Control)context.Instance).Site;
            var columnsProperty = TypeDescriptor.GetProperties(dataGridView1)["Columns"];
            var tdc = new TypeDescriptionContext(dataGridView1, columnsProperty);
            var editor = (UITypeEditor)columnsProperty.GetEditor(typeof(UITypeEditor));
            var result = editor.EditValue(tdc, provider, value);
            dataGridView1.Site = null;
            return result;
        }
    }

TypeDescriptionContext:

public class TypeDescriptionContext : ITypeDescriptorContext
    {
        private Control editingObject;
        private PropertyDescriptor editingProperty;
        public TypeDescriptionContext(Control obj, PropertyDescriptor property)
        {
            editingObject = obj;
            editingProperty = property;
        }
        public IContainer Container
        {
            get { return editingObject.Container; }
        }
        public object Instance
        {
            get { return editingObject; }
        }
        public void OnComponentChanged()
        {
        }
        public bool OnComponentChanging()
        {
            return true;
        }
        public PropertyDescriptor PropertyDescriptor
        {
            get { return editingProperty; }
        }
        public object GetService(Type serviceType)
        {
            return editingObject.Site.GetService(serviceType);
        }
    }

我知道 Vb.net 但不是专业人士并将此代码 C# 转换为 VB.net

问题出在哪里？预先感谢您的帮助

Answer 1

我发现了问题

在VB.NetWhen Add Datagridview to UserControl in Designer Cod Is defined has:

Friend WithEvents Dgv1 As System.Windows.Forms.DataGridView

没错

Private Dgv1 As System.Windows.Forms.DataGridView

甚至不应该是那样

Private WithEvents Dgv1 As System.Windows.Forms.DataGridView

太可惜了

我决定转向 C#

在 UserControl 中单击属性时错误打开 "Edit Columns"

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在 UserControl 中单击属性时错误打开 "Edit Columns"