vb listview控件中如何在选中某一行时将此行的第3列数据提取到文本框中显示，急！

Dim i As Integer

Private Sub Command1_Click()
With ListView1.ListItems.Add
.SubItems(1) = i & "a"
.SubItems(2) = i & "b"
.SubItems(3) = i & "c"
End With

i = i + 1
End Sub

Private Sub Command2_Click()
Text1.Text = ListView1.SelectedItem.SubItems(3)
End Sub

Private Sub Form_Load()
ListView1.View = lvwReport
ListView1.ColumnHeaders.Clear
With ListView1.ColumnHeaders
.Add , , "", 10
.Add , , "第一列", 1000
.Add , , "第二列", 2000
.Add , , "第三列", 2000
End With

i = 1
End Sub

不清出你的具体格式，暂且认为：
1 A a
2 B b
3 C c
每个字符间有一个空格，每行的后面（如小a后面）都有一个空格，代码如下
Private Sub Command1_Click()
Dim tmpGrp() As String '用于存放分解后的text1内容
tmpGrp = Split(Text1.Text, " ")
Dim i As Integer
Dim tmpRst As String
For i = 0 To UBound(tmpGrp) Step 3
If i + 1 < UBound(tmpGrp) Then
tmpRst = tmpRst & IIf(tmpRst = "", "", vbCrLf) & tmpGrp(i + 1)
End If
Next i
Text2.Text = tmpRst
End Sub

楼上很正确，我也学习了