Private Sub Button1_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles Button1.Click Dim r As New StreamReader(Application.StartupPath & \ABC.txt, System.Text.Encoding.Default) '用StreamReader打开文本文件 Dim s As String TextBox1.Text = Do While r.Peek -1 '是否到文件尾 s = r.ReadLine '从打开的文件中读取一行内容 TextBox1.Text = TextBox1.Text & s & vbCrLf '添加到文本框TextBox1.Text的后面并回车 Loop r.Close() '关闭对象 End Sub End Class