一.TreeView

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

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);
}
}

數據篩選和排序------的解析