一个多行文本框，
里面有N行内容，
请问
如何每点一次按钮，
就自动删除前3行内容，直到文本内容全部清空为止
谢谢

确实没这么玩过，但摸索了一下，发现多行之间实际是有“回车”和“换行”符的，借助这个可以实现你的要求，这个可以点击一下删除一行，你再改改吧

Dim Arr() As String
Dim Temp As String
If Text1.Text <> "" Then
If InStr(Text1.Text, vbCrLf) > 0 Then
Temp = ""
Arr = Split(Text1.Text, vbCrLf)
If UBound(Arr) > 1 Then
For i = 3 To UBound(Arr)
If Temp = "" Then
Temp = Arr(i)
Else
Temp = Temp & vbCrLf & Arr(i)
End If
Next
Text1.Text = Temp
End If
End If
End If

Dim Temp As String
Dim i As Long
Dim NumberRows As Long
NumberRows = 3 '修改3为要删除的行数
i = 0
Temp = Text1.Text
If Temp <> "" Then
Do While InStr(Temp, vbCrLf) > 0
i = i + 1
Temp = Mid(Temp, InStr(Temp, vbCrLf) + 1, Len(Temp) - InStr(Temp, vbCrLf) )
If i = NumberRows Then
Exit Do
End If
Loop
Text1.Text = Temp
End If

上面这些办法用于有回车的内容，而如果是连续长内容就会不一样很麻烦，
我发现一个Private Declare Function lstrlen Lib "kernel32" Alias "lstrlenA" (ByVal lpString As String) As Long可以返回中英混合文本所占长度，考虑用循环找出每行第几个字符是行尾，然后就可删掉前面

参考图片

Option Explicit
Private Declare Function lstrlen Lib "kernel32" Alias "lstrlenA" (ByVal lpString As String) As Long
Private Sub Command1_Click()
Text1.Text = DeleteLine(Text1.Text, 41, 3) '这里假设文本框一行41个半角字符
End Sub
Private Sub Form_Load()
Dim ILoad As Integer
Dim SLoad As String
SLoad = ""
For ILoad = 1 To 30
SLoad = SLoad & "1234567890"
Next ILoad
Text1.Text = SLoad
End Sub
Function DeleteLine(ByVal DeleteText As String, ByVal LineLength As Integer, ByVal DeleteRow As Integer) As String
Dim s As String
Dim n As Integer
Dim i As Integer
Dim j As Integer
DeleteLine = DeleteText
s = DeleteText
For j = 1 To DeleteRow
n = 0
For i = 1 To LineLength + 10
If lstrlen(Left(s, i)) = LineLength - 1 And lstrlen(Left(s, i + 1)) = LineLength + 1 Then
n = i
ElseIf lstrlen(Left(s, i)) = LineLength Then
n = i
End If
Next i
If n > 0 Then
s = Mid(s, n + 1)
Else
s = ""
End If
Next j
DeleteLine = s
End Function

我刚刚发现，文本框中用鼠标点击行尾然后加回车，可能会比仅用键盘加回车，看起来要少一空行，可是两者的实际内容却是完全一样的，这样我并不确定楼主需求是删除几行，所以我这个还是算失败的不能用

Dim Temp As String
Dim Arr() As String
Dim NumberRows As Long
NumberRows = 3 '修改3为要删除的行数
If Text1.Text <> "" Then
Arr = Split(Text1.Text, vbCrLf)
If UBound(Arr) > 2 Then
For i = 0 To NumberRows - 1
If Temp = "" Then
Temp = Arr(i)
Else
Temp = Temp & vbCrLf & Arr(i)
End If
Next
Temp = Temp & vbCrLf
Text1.Text = Mid(Text1.Text, Len(Temp), Len(Text1.Text) - Len(Temp) + 1)
End If
End If

'再提供一个能处理回车的整合版
'在窗体上放置一个文本框Text1，并将其MultiLine属性设为True
'在窗体上放置一个按钮Command1
'运行程序，记住Text1每行最大多少个数字，替换41
Option Explicit
Private Declare Function lstrlen Lib "kernel32" Alias "lstrlenA" (ByVal lpString As String) As Long
Private Sub Command1_Click()
Text1.Text = DeleteLine(Text1.Text, 41, 3) '这里假设文本框一行41个半角字符
End Sub
Private Sub Form_Load()
Dim ILoad As Integer
Dim SLoad As String
SLoad = ""
For ILoad = 1 To 30
SLoad = SLoad & "1234567890"
Next ILoad
Text1.Text = SLoad
End Sub
Function DeleteLine(ByVal DeleteText As String, ByVal LineLength As Integer, ByVal DeleteRow As Integer) As String
Dim DeleteLineS As String
Dim DeleteLineN As Integer
Dim DeleteLineI As Integer
Dim DeleteLineJ As Integer
Dim DeleteLineB As Boolean
DeleteLine = DeleteText
DeleteLineS = DeleteText
For DeleteLineJ = 1 To DeleteRow
DeleteLineN = 0
DeleteLineB = True
For DeleteLineI = 1 To LineLength + 1
If lstrlen(Left(DeleteLineS, DeleteLineI)) <= LineLength + 1 Then
If Mid(DeleteLineS, DeleteLineI, 2) = vbCrLf Then
DeleteLineS = Mid(DeleteLineS, DeleteLineI + 2)
DeleteLineB = False
Exit For
Else
If lstrlen(Left(DeleteLineS, DeleteLineI)) = LineLength - 1 And lstrlen(Left(DeleteLineS, DeleteLineI + 1)) = LineLength + 1 Then
DeleteLineN = DeleteLineI
ElseIf lstrlen(Left(DeleteLineS, DeleteLineI)) = LineLength Then
DeleteLineN = DeleteLineI
End If
End If
End If
Next DeleteLineI
If DeleteLineB Then
If DeleteLineN > 0 Then
DeleteLineS = Mid(DeleteLineS, DeleteLineN + 1)
Else
DeleteLineS = ""
End If
End If
Next DeleteLineJ
DeleteLine = DeleteLineS
End Function