Question

我正在将VB6项目转换为C＃.net VB6代码是。

 Dim ctlControl As VB.VBControlExtender
 Dim objControl As DocSys.IControl



If blnRetVal Then

    ' get IControl interface
    On Error Resume Next
    Set objControl = ctlControl.object
    blnRetVal = objControl.Load(strName, ndControl, objField, objTab.Model)

其中用户控件正在动态使用 objControl的类型是IControl，它是一个接口。 IControl在许多用户控件中实现，如（按钮，Chekbox，地址等）。

我正在将此代码转换为C＃.net 代码是

Control ctlControl = new Control();
DocSys.IControl objControl = default(DocSys.IControl);
 if (blnRetVal)
  {                    
    objControl = (IControl)ctlControl;  
     blnRetVal = objControl.Load(strName, ndControl, objField, objTab.Model);
  }

它显示了一个异常ctlControl：

Cannot cast 'ctlControl' (which has an actual type of 'System.Windows.Forms.Control') to 'DocSys.IControl'  DocSys.IControl

Answer 1

大多数WinForm控件都继承自System.Windows.Forms.Control，如果您希望控件实现IControl-Interface，则必须扩展基本控件。

喜欢：

public class MyTextBox : System.Windows.Forms.TextBox, DocSys.IControl
{
    public string Test() // Function of IControl
    {
        throw new NotImplementedException();
    }
}

要动态添加控件到您的表单，您可以使用此示例代码：

public partial class Form1 : Form
{
    public Form1()
    {
        InitializeComponent();

        MyTextBox textBox = new MyTextBox();
        textBox.Text = "Textbox content";
        textBox.Location = new Point(25, 25);
        this.Controls.Add(textBox);
    }
}

How to programmatically add controls to Windows forms at run time

Answer 2

丹尼斯我已经完成了这个

public partial class CanvasCtl: UserControl,IControl
  {
    public bool Load(string strName, System.Xml.XmlElement ndControl, IField objField, Model objModel)
    {
        m_strName = strName;
        m_Field = objField;

        this.Enabled = true;

        return Init(ref ndControl);

    }
   }

在ChekBox类和CanvasCtl类中相同问题是我正在动态使用它们

Control ctlControl = new Control();
DocSys.IControl objControl = default(DocSys.IControl);

 ctlControl = (Control)objTab.CanvasCtl.GetCtl(strName);
 if (blnRetVal)
  {                    
  objControl = (IControl)ctlControl;  
   blnRetVal = objControl.Load(strName, ndControl, objField, objTab.Model);
  }

就行了

 objControl = (IControl)ctlControl;

它显示异常

Cannot cast 'ctlControl' (which has an actual type of 'System.Windows.Forms.Control') to 'DocSys.IControl'  DocSys.IControl

Answer 3

在VB6中，您需要VBControlExtender对象，以便使用Add方法将控件动态添加到Controls集合中。

它主要用于ActiveX控件。

例如

Dim WithEvents dynamicFlexGrid As VBControlExtender

您可以执行以下操作：

Set dynamicFlexGrid = Controls.Add("MSFlexGridLib.MSFlexGrid.1", ,"FlexGrid1")
   With dynamicFlexGrid.object  
   For r = 1 To .Rows - 1  
      For c = 1 To .Cols - 1  
         .TextMatrix(r, c) = "r"  & r & "c" & c  
      Next  
   Next 
dynamicFlexGrid.Height = 300
dynamicFlexGrid.Width = 300
dynamicFlexGrid.Visible = True

在.NET中，要托管ActiveX，您需要AxHost子类。您可以创建一个简单的帮助程序，例如：

namespace UpgradeHelpers
{
    public class AxControl : AxHost
    {
        public AxControl(string strCLSID) : base(strCLSID)
        {
        }
    }


    public static class ControlExtenderHelper
    {
        public static AxHost AddExtended(this System.Windows.Forms.Control.ControlCollection controls, string progId, string controlName)
        {
            Type type = Type.GetTypeFromProgID(progId, true);
             var newControl = new AxControl(controlType.GUID.ToString());
            newControl.Name = controlName;
            controls.Add(newControl);
            return newControl;
        }
    }
}

然后您可以将变量声明为

   AxHost dynamicVSFlexGrid;

并像这样使用它：

            dynamicFlexGrid = Controls.AddExtended("MSFlexGridLib.MSFlexGrid.1", "FlexGrid1");

有关更多详细信息，请参见我的帖子：https://www.mobilize.net/blog/dynamically-adding-activex-in-c

什么是.net中的VBControlExtender的替代品

3 个答案: