Cmd控件表单VB.NET [英] Cmd control form VB.NET

问题描述

在Windows窗体中启动cmd会话命令ipconfig

但是在 显示错误FnctionStartConsoleEvent

有人帮我吗？



我尝试过的事情：

start a cmd session in a windows form whit command "ipconfig"
but show an error on FnctionStartConsoleEvent
anyone help me?

What I have tried:

Dim cdd() As String
    Event Avvia()
    Function FnctionStartConsoleEvent(e As KeyEventArgs) As EventHandler(Of ComboBox.ObjectCollection)
        If e.KeyData = Keys.Enter Then
            Dim process As Process = New Process
            With process
                '  .StartInfo.ErrorDialog = False
                .StartInfo.RedirectStandardInput = True
                .StartInfo.RedirectStandardOutput = True
                .StartInfo.UseShellExecute = False
                .StartInfo.FileName = "cmd.exe"
                .StartInfo.CreateNoWindow = True
                .StartInfo.WindowStyle = ProcessWindowStyle.Hidden
            End With
            process.Start()
            Try
                process.StandardInput.WriteLine("cd/d " & cdd(3))
            Catch
            End Try
            process.StandardInput.WriteLine(ComboBox1.Text)
            process.StandardInput.WriteLine("echo [~cd~]%cd%[~cd~]")
            process.StandardInput.WriteLine("exit")
            Dim outpp As New TextBox
            outpp.Text = process.StandardOutput.ReadToEnd
            cdd = Split(outpp.Text, "[~cd~]")

            For i = 4 To outpp.Lines.Length - 6
                RichTextBox1.Text = RichTextBox1.Text & outpp.Lines(i).Substring(0) & vbCrLf
            Next
            ComboBox1.Items.Add(ComboBox1.Text)
            ComboBox1.Text = ""
            RichTextBox1.SelectionStart = RichTextBox1.Text.Length
            RichTextBox1.ScrollToCaret()
        End If
    End Function

    Private Sub ComboBox1_SelectedIndexChanged(sender As Object, e As EventArgs) Handles ComboBox1.SelectedIndexChanged
        AddHandler Avvia, AddressOf FnctionStartConsoleEvent
        If ComboBox1.SelectedText = "ipconfig" Then
            RaiseEvent Avvia()
        End If
    End Sub

推荐答案

第一个问题：

您有一个期望零参数的事件。



您正在尝试添加一个处理器方法，该方法需要一个参数 - 一个 KeyEventArgs 实例。



事件处理程序必须匹配他们处理的事件的签名。如果没有，则会出现屏幕截图中显示的编译错误。

---

第二个问题：

您已声明 FnctionStartConsoleEvent 返回一个事件处理程序方法，该方法将接受两个参数 - sender As Object 和 args As ComboBox.ObjectCollection 。



该方法没有这样的事情。



由于该方法没有返回任何内容，VB有帮助插入返回Nothing 在函数退出之前。如果您尝试使用返回值，您将获得 NullReferenceException 。

---

您需要重新开始，并阅读一些有关事件如何工作的教程。



事件（Visual Basic） [ ^ ]

提升事件和响应事件 [ ^ ]

演练：声明和提升事件（Visual Basic） [ ^ ]

Step by Ste p：VB.NET中的事件处理 [ ^ ]

First problem:
You have an event which expects zero arguments.

You are trying to add a handler method which expects one argument - a KeyEventArgs instance.

Event handlers MUST match the signature of the event they handle. If they don't, you get the compiler error shown in your screen-shot.

---

Second problem:
You have declared that FnctionStartConsoleEvent returns an event handler method which will accept two arguments - sender As Object and args As ComboBox.ObjectCollection.

The method does no such thing.

Since the method doesn't return anything, VB "helpfully" inserts a Return Nothing before the function exits. If you try to use the return value, you will get a NullReferenceException.

---

You need to start again, and read a few tutorials on how events work.

Events (Visual Basic)[^]
Raising Events and Responding to Events[^]
Walkthrough: Declaring and Raising Events (Visual Basic)[^]
Step by Step: Event handling in VB.NET[^]

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