部门树的思想:
第一步,查询出所以部门信息。
public DataTable GetAllDeptInfo()
{
//数据访问采用最原始的ADO.NET技术,现在最好的方式是NHibernate,读者可以自己换
string connstr = "data source=localhost;Integrated Security=SSPI;initial catalog=Study";//数据库连接字符串有多种,因为我的数据库采用的是Windows认证方式,所以采用Integrated Security=SSPI,若不是则采用uid=用户名;pwd=密码。
SqlConnection conn= new SqlConnection(connstr);
if(conn.State==ConnectionState.Closed)
conn.Open();
SqlCommand com = conn.CreateCommand();
string sql = "select * from DeptInfo";
DataTable myTable = new DataTable();
com.CommandText=sql;
SqlDataAdapter sda = new SqlDataAdapter(com);
sda.Fill(myTable);
if (conn.State == ConnectionState.Open) conn.Close();
return myTable;
}
protected void Page_Load(object sender, EventArgs e)
{
DataTable dtParam = GetAllDeptInfo();
DataTable dtTree = dtParam.Clone();
//克隆出与dtParam一样架构但没有数据的表
BuildTree(dtTree, dtParam, 0, "0");//从根部门出发
DropDownList1.DataSource = dtTree;
DropDownList1.DataTextField = dtTree.Columns[2].ToString();
DropDownList1.DataValueField = dtTree.Columns[0].ToString();
DropDownList1.DataBind();
}
接下来写递归方法,思想为dtTree加入当前的行,并将非当行前指派到下一递归。
public void BuildTree(DataTable dtTree, DataTable dtParam, int intLevel, string parentid)
{
intLevel++;
string strLeftPre = "";
//设置前辍
if (intLevel > 1)
{
strLeftPre = "|" + strLeftPre.PadLeft(intLevel*2,'-');
}
DataTable currTable = new DataTable();
currTable = dtParam.Clone();//用来记录当前行
DataTable nextTable = new DataTable();
nextTable = dtParam.Clone();//用来记录非当前行,也就是剩余行,此方法很好,不需要重复遍历。
for (int i = 0; i < dtParam.Rows.Count; i++)
{
if (dtParam.Rows[i][1].ToString() == parentid)//判断是否为当前行,如是加入currTable,否则加入nextTable
currTable.Rows.Add(dtParam.Rows[i].ItemArray);
}
else
{
nextTable.Rows.Add(dtParam.Rows[i].ItemArray);
}
}
for (int j = 0; j < currTable.Rows.Count; j++)
{
DataRow dr = currTable.Rows[j];
dr[2] = strLeftPre + dr[2].ToString();
dtTree.Rows.Add(dr.ItemArray);//将当前行插入dtTree
BuildTree(dtTree, nextTable, intLevel, dr[0].ToString());//处理当前行的子部门
}
}