ListBox实现简单选课系统

1.效果图

 异常处理

 正解

//添加新的课程 private void btnAddCourse_Click(object sender, EventArgs e) { bool exit = false; if (txtCourse.Text == "") MessageBox.Show("所添加的课程不能为空。"); else { for (int i = 0; i < lbCourse.Items.Count; i++) if (txtCourse.Text == lbCourse.Items[i].ToString()) { MessageBox.Show("不能添加重复的课程。"); exit = true; txtCourse.Clear(); break; } if (exit == false) { lbCourse.Items.Add(txtCourse.Text); txtCourse.Clear(); } } }

 

//”->”按钮单击事件 private void btnToRight_Click(object sender, EventArgs e) { try { this.lbSelectCourse.Items.Add(this.lbCourse.SelectedItem); this.lbCourse.Items.Remove(this.lbCourse.SelectedItem); } catch (Exception exp) { MessageBox.Show(exp.Message); } } //”<-”按钮单击事件 private void btnToLeft_Click(object sender, EventArgs e) { try { this.lbCourse.Items.Add(this.lbSelectCourse.SelectedItem); this.lbSelectCourse.Items.Remove (this.lbSelectCourse.SelectedItem); } catch (Exception exp) { MessageBox.Show(exp.Message); } } //”>>”按钮单击事件 private void btnToRightAll_Click(object sender, EventArgs e) { for (int i = 0; i < this.lbCourse.Items.Count; i++) { this.lbSelectCourse.Items.Add(this.lbCourse.Items[i]); } this.lbCourse.Items.Clear(); } //”<<”按钮单击事件 private void btnToLeftAll_Click(object sender, EventArgs e) { for (int i = 0; i < this.lbSelectCourse.Items.Count; i++) { this.lbCourse.Items.Add(this.lbSelectCourse.Items[i]); } this.lbSelectCourse.Items.Clear(); }

错误代码！！！

 

private void btn_submit_Click(object sender, EventArgs e) { //把新的课程添加到课程里面 list_exist_course.Items.Add(txt_add.Text); } //把选中的item移到右边 private void btn_right_Click(object sender, EventArgs e) { try { list_select_course.Items.Add(list_exist_course.SelectedItem);//把选中的放到右边 list_exist_course.Items.Remove(list_exist_course.SelectedItem);//删掉选中的 } catch (Exception) { MessageBox.Show("没有选中任何课程！"); // throw; } } //把选中的item移到左边 private void btn_left_Click(object sender, EventArgs e) { try { list_exist_course.Items.Add(list_select_course.SelectedItem);//把选中的放到左边 list_select_course.Items.Remove(list_select_course.SelectedItem);//删掉选中的 } catch (Exception) { MessageBox.Show("没有选中任何课程！");//异常没有抛出来 } } private void btn_rightAll_Click(object sender, EventArgs e) { int a =0; while (a < 4) {//循环四次 for (int i = 0; i < list_exist_course.Items.Count; i++) { list_select_course.Items.Add(list_exist_course.Items[i]);//把左边的全部移动到右边 list_exist_course.Items.RemoveAt(i); } a++; }//循环四次 } private void btn_leftALL_Click(object sender, EventArgs e) { int a =0; while (a < 4) {//循环四次 for (int i = 0; i < list_select_course.Items.Count; i++)//把右边的全部左边 { list_exist_course.Items.Add(list_select_course.Items[i]); list_select_course.Items.RemoveAt(i); } a++; }//循环四次 }

 本程序还有很多不足希望大家指出来，欢迎留言