VB2010实例(1)_字符大小写转换

Public Class Form1

    Private Sub Form1_Load(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles MyBase.Load
        Label3.Text = "e.KeyChar:"
        Label4.Text = "e.KeyChar的值："
    End Sub
    '清除文体框
    Private Sub Button1_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles Button1.Click
        TextBox1.Text = ""
        TextBox2.Text = ""
    End Sub
    '退出
    Private Sub Button2_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles Button2.Click
        Me.Close()
    End Sub

    Private Sub TextBox1_KeyPress(ByVal sender As Object, ByVal e As System.Windows.Forms.KeyPressEventArgs) Handles TextBox1.KeyPress
        Label3.Text = Mid(Label3.Text, 1, 10) & e.KeyChar
        Label4.Text = Mid(Label4.Text, 1, 10) & Convert.ToInt32(e.KeyChar)
        Dim str As String
        str = e.KeyChar
        Select Case str
            Case "a" To "z"
                str = Chr(Convert.ToInt32(e.KeyChar) - 32)
            Case "A" To "Z"
                str = Chr(Convert.ToInt32(e.KeyChar) + 32)
            Case Else
                str = "*"
        End Select
        TextBox2.Text = TextBox2.Text & str
    End Sub
End Class