c#數據篩選和排序

一.TreeView

            SelectedNode    選中的節點
            Level    節點的深度（從0開始）    
            AfterSelect    節點選中后發生

            1.獲取節點深度

                this.tvlist.SelectNode.Level

            2.獲取節點名稱

                this.tvlist.SelectNode.Text

        二.使用DataView篩選和排序數據

            RowFilter指定篩選條件
            Sort指定排序方式

            //窗體運行時默認選中全部
            if (this.tvstulist.SelectedNode.Level == 0) {
                ShowStudent();
            }
            else if (this.tvstulist.SelectedNode.Level == 1) {
                DataView dv = new DataView(ds.Tables["Student"]);
                dv.RowFilter = "GradeName='"+this.tvstulist.SelectedNode.Text+"'";
                this.dgvstulist.DataSource = dv;
            }
            else if (this.tvstulist.SelectedNode.Level == 2) {
                
                DataView dv = new DataView(ds.Tables["Student"]);
                dv.RowFilter = "GradeName='" + this.tvstulist.SelectedNode.Parent.Text + "' and Sex='" + this.tvstulist.SelectedNode.Text + "'";
                dv.Sort = "StudentNo desc";
                this.dgvstulist.DataSource=dv;
            }

        三.刪除數據

            SelectionMode指定選中DataGradeView的選中方式

            DialogResult result= MessageBox.Show("是否刪除","提示",MessageBoxButtons.YesNo,MessageBoxIcon.Information);
            if (result == DialogResult.Yes) {
                //獲取選中的學號的值
                int studentno=(int)this.dgvstulist.SelectedRows[0].Cells["StudentNo"].Value;
                try
                {
                    helper.OpenConnection();
                    string sql = "delete from Student where StudentNo='"+studentno+"'";
                    SqlCommand cmd = new SqlCommand(sql,helper.Con);
                    int count=cmd.ExecuteNonQuery();
                    if (count > 0)
                    {
                        MessageBox.Show("刪除成功！", "提示", MessageBoxButtons.OK, MessageBoxIcon.Information);
                        ShowStudent();
                    }
                    else {
                        MessageBox.Show("刪除失敗！", "提示", MessageBoxButtons.OK, MessageBoxIcon.Information);
                    }
                }
                catch (Exception x)
                {
                    MessageBox.Show(x.Message);
                }
            }