取出特定符号后15位字符串，高手们来看看那里错了！请指点，谢谢！
代码：
    Private Sub Button2_Click(sender As Object, e As EventArgs) Handles Button2.Click
        Dim X = TextBox1.Text
        Dim z As Byte
        For i = 1 To Len(X)
            z = Mid(X, InStr("=", X), 15)
            z = z + 1
        Next i
        Me.TextBox2.AppendText(z)
    End Sub

TextBox1文本框内容：
RID   =1234                       TID   =XINJIANGWAN                    
>51   = 200      
>>34  = OFF      

结果输入到TextBox2文本框中，并如下排列：
1234           ，
XINJIANGWAN    ，
200            ，
OFF            ，

    Private Sub Button1_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles Button1.Click
        Dim X = TextBox1.Text
        Dim z As String
        z = Mid(X, InStr(TextBox1.Text, "=") + 1, 15) ' + InStr(TextBox1.Text, "="))
        TextBox2.Text = z
    End Sub

谢谢了！！！！1

不好意思，忘记给分，第一次来这。抱歉！！！