List<string> list = new List<string>();//首先定义一个泛型数组 //这里假如说有四个文本框 string mainseat = this.textBox1.Text; string nextseat = this.textBox2.Text; string storeseat1 = this.textBox3.Text; string storeseat2 = this.textBox4.Text; if (mainseat != "") {      list.Add(mainseat); } if (nextseat != "") {       list.Add(nextseat); } if (storeseat1 != "") {       list.Add(storeseat1); } if (storeseat2 != "") {        list.Add(storeseat2); }     if (list.Distinct().Count<string>() != list.Count)//排查数组中是否有重复元素 {        //此时说明有重复 }           else        //说明没有重复