变量“名称"在被赋值之前使用 [英] Variable 'Name' is used before it has been assigned a value

问题描述

你好，我想聊天，我在互联网上搜索，我终于找到了一些可能有用的东西.但现在我在 name 上收到一个错误，它说在分配值之前使用了变量名

hello i wanted to make a chat and i searched on the internet and i finaly found something that may work. but now i get an error at name it says Variable Name is used before it has assigned a value

代码:

Public Sub findForm1()

    If Trim(Mid(My.Forms.Private1.Text, My.Forms.Private1.Text.Length - 2)) = formNo Then
        My.Forms.Private1.RichTextBox1.Text = My.Forms.Private1.RichTextBox1.Text & poruka + vbCrLf

    ElseIf Trim(Mid(My.Forms.Private2.Text, My.Forms.Private2.Text.Length - 2)) = formNo Then
        My.Forms.Private2.RichTextBox1.Text = My.Forms.Private2.RichTextBox1.Text & poruka + vbCrLf

    Else
        If My.Forms.Private1.Visible = False Then
            Dim name As String
            For i As Integer = 1 To poruka.Length
                If Mid(poruka, i, 2) = ": " Then
                    Exit For

                    name = name & Mid(poruka, i, 1)
                End If
            Next
            My.Forms.Private1.Show()
            My.Forms.Private1.Text = Trim(name) & "   " & br
            My.Forms.Private1.RichTextBox1.Text = My.Forms.Private1.RichTextBox1.Text & poruka + vbCrLf
        Else
            Dim name As String
            For i As Integer = 1 To poruka.Length
                If Mid(poruka, i, 2) = ": " Then
                    Exit For
                End If
                name = name & Mid(poruka, i, 1)
            Next
            My.Forms.Private2.Show()
            My.Forms.Private2.Text = Trim(name) & "   " & br
            My.Forms.Private2.RichTextBox1.Text = My.Forms.Private2.RichTextBox1.Text & poruka + vbCrLf
        End If
    End If

    formNo = Nothing
    poruka = Nothing

End Sub

我该如何修复这个错误??我已经尝试移动结束 if 并更改其他一些以结束 if.但仍然没有找到正确的代码请帮助.

how can i fix this error?? i already tried to move the end if and change some else to end if. but still not find the right code PLEAS HELP.

推荐答案

是的，编译器完全正确.您的代码中的问题可以归结为以下内容:

Yes, the compiler's absolutely right. The problem in your code can be boiled down to something like this:

Dim name as String
name = name & "Foo"

您正在尝试将 name 的 current 值与另一个字符串 ("Foo") 连接起来 - 但 name 没有 还有一个值.

You're trying to concatenate the current value of name with another string ("Foo") - but name doesn't have a value yet.

您可以将其更改为:

Dim name as String = ""
name = name & "Foo"

...但是您最好使用 StringBuilder.例如，您的第一个循环可能是:

... but you'd be better off using a StringBuilder. So for example, your first loop could be:

Dim nameBuilder As StringBuilder = New StringBuilder()
For i As Integer = 1 To poruka.Length
    If Mid(poruka, i, 2) = ": " Then
        Exit For

        nameBuilder.Append(Mid(poruka, i, 1))
    End If
Next
My.Forms.Private1.Show()
My.Forms.Private1.Text = Trim(nameBuilder.ToString()) & "   " & br

这篇关于变量“名称"在被赋值之前使用的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持IT屋！