按钮一点，判断txt是否为空，不是则在lbl显示 hello world!
加载form的时候，跳出输入对话框，不空择在Lbl显示 hello,world!
Private Sub Button1_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles Button1.Click
If Len(TextBox1.Text) <> 0 Then
Label1.Text = "Hello," + TextBox1.Text + "!"
End If
End Sub
Private Sub TextBox1_MouseDown(ByVal sender As Object, ByVal e As System.Windows.Forms.MouseEventArgs) Handles TextBox1.MouseDown
TextBox1.Text = ""
End Sub
Private Sub Form1_Load(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles MyBase.Load
Dim name As String
name = InputBox("Input ur name!", "Input name", , , )
If name <> "" Then
Label1.Text = "Hello," + name + "。"
End If
End Sub
End Class
