“a"不包含“&;b"”的定义.且无扩展方法'b & # 39;接受类型的第一个参数

本文关键字：quot 类型 参数 第一个 包含 定义 扩展 方法 | 更新日期: 2023-09-27 18:17:48

我得到了一个错误，我无法修复:

Error 1 'System.Windows.Forms.Label' does not contain a definition for 'Copy' 
and no extension method 'Copy' accepting a first argument of     
type'System.Windows.Forms.Label' 
could be found (are you missing a using directive or an assembly reference?)
//path 156  22 FileWatcherEigen

那是我的错误。有人能帮我解释一下哪里出了问题吗?

这是我的代码:

using System;
using System.IO;
using System.Collections.Generic;
using System.ComponentModel;
using System.Data;
using System.Drawing;
using System.Linq;
using System.Text;
using System.Windows.Forms;
namespace WindowsFormsApplication1
{
public partial class Form1 : Form
{
    private bool pause = false;
    private bool cut1 = false;
    private bool copy1 = false;
    public Form1()
    {
        InitializeComponent();
    }

    // The lines with performed actions of a file
  private void fileSystemWatcher1_Created(object sender,System.IO.FileSystemEventArgs e)
    {
        if (!pause)
        {
            listBox1.Items.Add("File Created> " + e.FullPath + " -Date:" + DateTime.Now);
        }
    }
    private void fileSystemWatcher1_Changed(object sender, System.IO.FileSystemEventArgs e)
    {
        if (!pause)
        {
            listBox1.Items.Add("File Changed> " + e.FullPath + " -Date:" + DateTime.Now);
        }
    }
    private void fileSystemWatcher1_Deleted(object sender, System.IO.FileSystemEventArgs e)
    {
        if (!pause)
        {
            listBox1.Items.Add("File Deleted> " + e.FullPath + " -Date:" + DateTime.Now);
        }
    }
    private void fileSystemWatcher1_Renamed(object sender, System.IO.RenamedEventArgs e)
    {
        if (!pause)
        {
            listBox1.Items.Add("File Renamed> " + e.FullPath + " -Date:" + DateTime.Now);
        }
    }
    private void fileSystemWatcher2_Changed(object sender, System.IO.FileSystemEventArgs e)
    {
        if (!pause)
        {
            listBox1.Items.Add("File Changed> " + e.FullPath + " -Date:" + DateTime.Now);
        }
    }
    private void fileSystemWatcher2_Created(object sender, System.IO.FileSystemEventArgs e)
    {
        if (!pause)
        {
            listBox1.Items.Add("File Created> " + e.FullPath + " -Date:" + DateTime.Now);
        }
    }
    private void fileSystemWatcher2_Deleted(object sender, System.IO.FileSystemEventArgs e)
    {
        if (!pause)
        {
            listBox1.Items.Add("File Deleted> " + e.FullPath + " -Date:" + DateTime.Now);
        }
    }
    private void fileSystemWatcher2_Renamed(object sender, System.IO.RenamedEventArgs e)
    {
        if (!pause)
        {
            listBox1.Items.Add("File Renamed> " + e.FullPath + " -Date:" + DateTime.Now);
        }
    }
    //1st directory
    private void button2_Click(object sender, EventArgs e)
    {
        if (dlgOpenDir.ShowDialog() == DialogResult.OK)
        {
            fileSystemWatcher1.EnableRaisingEvents = false;  // Stop watching
            fileSystemWatcher1.IncludeSubdirectories = true;
            fileSystemWatcher1.Path = dlgOpenDir.SelectedPath;
            textBox1.Text = dlgOpenDir.SelectedPath;         // Text of textBox2 = Path of fileSystemWatcher2
            fileSystemWatcher1.EnableRaisingEvents = true;   // Begin watching
        }
    }
    //2nd directory
    private void button3_Click(object sender, EventArgs e)
    {
        if (dlgOpenDir.ShowDialog() == DialogResult.OK)
        {
            fileSystemWatcher2.EnableRaisingEvents = false;  // Stop watching
            fileSystemWatcher2.IncludeSubdirectories = true;
            fileSystemWatcher2.Path = dlgOpenDir.SelectedPath;
            textBox2.Text = dlgOpenDir.SelectedPath;         // Text of textBox2 = Path of fileSystemWatcher2
            fileSystemWatcher2.EnableRaisingEvents = true;   // Begin watching
        }
    }
    //log
    private void button1_Click(object sender, EventArgs e)
    {
        DialogResult resDialog = dlgSaveFile.ShowDialog();
        if (resDialog.ToString() == "OK")
        {
            FileInfo fi = new FileInfo(dlgSaveFile.FileName);
            StreamWriter sw = fi.CreateText();
            foreach (string sItem in listBox1.Items)
            {
                sw.WriteLine(sItem);
            }
            sw.Close();
        }
    }
    //pause watching
    private void pause_button_Click(object sender, EventArgs e)
    {
        if (!pause)
        {
            pause = true;
            pause_button.Text = "Unpause";
        }
        else
        {
            pause = false;
            pause_button.Text = "Pause Watching";
        }
    }
    //clear listbox
    private void clear_button_Click(object sender, EventArgs e)
    {
        listBox1.Items.Clear(); 
    }
    private void Transfer_Click(object sender, EventArgs e)
    {
        if (copy1)
        {
            File.Copy(FileBrowseBox.Text, Path.Combine(DestinationBox.Text, Path.ChangeExtension(FileNameBox.Text, Path.GetExtension(FileBrowseBox.Text))));
        }
        }
    private void Browse_file_Click(object sender, EventArgs e)
    {
        DialogResult resDialog = openFileDialog1.ShowDialog();
        if (resDialog == DialogResult.OK)
        {
            FileBrowseBox.Text = openFileDialog1.FileName;
        }
    }
    private void Browse_destination_Click(object sender, EventArgs e)
    {
        DialogResult resDialog = folderBrowserDialog1.ShowDialog();
        if (resDialog == DialogResult.OK)
        {
            DestinationBox.Text = folderBrowserDialog1.SelectedPath;
        }
    }
    private void CopyButton_CheckedChanged(object sender, EventArgs e)
    {
        copy1 = true;
    }
}
}

它说问题在这部分:

 File.Copy(FileBrowseBox.Text, Path.Combine(DestinationBox.Text, Path.ChangeExtension(FileNameBox.Text, Path.GetExtension(FileBrowseBox.Text))));

我试着在这个论坛上找到它，但我真的找不到答案或解决方案

可以用下面的代码:

using System;
using System.IO;
using System.Collections.Generic;
using System.ComponentModel;
using System.Data;
using System.Drawing;
using System.Linq;
using System.Text;
using System.Windows.Forms;
namespace WindowsFormsApplication1
{
public partial class Form1 : Form
{
    private bool cut = false;
    private bool copy = false;
    public Form1()
    {
        InitializeComponent();
    }
    private void button1_Click(object sender, EventArgs e)
{
    File.Copy(FileBrowseBox.Text, Path.Combine(DestinationBox.Text, Path.ChangeExtension(FileBox.Text, Path.GetExtension(FileBrowseBox.Text))));
    label2.Text = "File Transfer Succeeded";
}
    private void button2_Click(object sender, EventArgs e)
    {
        DialogResult resDialog = openFileDialog1.ShowDialog();
        if (resDialog == DialogResult.OK)
        {
            FileBrowseBox.Text = openFileDialog1.FileName;
            label2.Text = "";
        }
    }
    private void button3_Click(object sender, EventArgs e)
    {
        DialogResult resDialog = folderBrowserDialog1.ShowDialog();
        if (resDialog == DialogResult.OK)
        {
            DestinationBox.Text = folderBrowserDialog1.SelectedPath;
            label2.Text = "";
        }
    }
    private void radioButton1_CheckedChanged(object sender, EventArgs e)
    {
        copy = true;
    }
    private void radioButton2_CheckedChanged(object sender, EventArgs e)
    {
        cut = true;
    }
}
}

“a"不包含“&;b"”的定义.且无扩展方法'b & # 39;接受类型的第一个参数

你得到这个错误，因为你有一个名为File的标签在你的表单上被引用，而不是System.IO.File。您可以重命名Label，这是我推荐的，或者您可以使用System.IO.File.Copy的完全限定路径来代替。

显然你有一个名为File的Label。它隐藏System.IO.File类并导致错误。指定完整的类名应该可以消除这个问题:

System.IO.File.Copy(...

我今天得到了这个烦人的错误，"a " DID包含了" b "的定义。

在VS2012中打开解决方案后，我进入了这个混乱，然后打开它VS2010。

结果是通过删除受影响项目中的参考DLL，构建参考DLL项目，然后重新引用允许VS看到定义

提醒一下。我在调试时也有类似的错误，在我重命名了类中的属性之后。检查了所有内容，甚至在所有解决方案中搜索了旧的属性名称ctrl+shift+f5。没有什么发现…

过了一会儿，我注意到现有的断点'When hit…

还有一种简单的情况会发生这种情况。假设您在表单中添加了一个工具，例如"按钮"。一旦你双击这个工具，(在Visual Studio中)代码private void button1_Click(object sender, EventArgs e) { }将在你的form .cs中创建。代码this.button1.Click += new System.EventHandler(this.button1_Click);也将在Form1.Designer.cs中创建。如果你删除了第一组代码(不管是什么原因)，那么你也需要删除第二位代码，否则你会得到这个错误。这可能是一个特定/简单的情况，但这是一个新程序员可能会遇到的错误。

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