1 private void button1_Click(object sender, EventArgs e) 2 { 3 this.errorProvider1.Clear(); 4 if (this.textBox1.Text.Length<6||this.textBox1.Text.Length>12) 5 { 6 this.errorProvider1.SetError(this.textBox1, "输入有误"); 7 DialogResult dialogresult = MessageBox.Show("你的输入有误", "Error", MessageBoxButtons.OKCancel); 8 switch (dialogresult) 9 { 10 case DialogResult.Cancel: 11 this.textBox1.Text = "你输入有误"; 12 break; 13 case DialogResult.OK: 14 this.textBox1.Text = ""; 15 break; 16 default: 17 break; 18 } 19 } 20 }