Http://community.csdn.net/Expert/topic/5229/5229675.xml? Temp =. 3458063.
BM data table structure:
ID name PID
First, let's take a look at the types of trees:
1. display the simple tree structure with only spaces or other identical symbols, such:Liberal arts Chinese Composition reading English Spoken and Written sciences physical chemistry
2. Use different symbols to display the tree structure and use spaces to move the subnode to the right. For example:Liberal arts, Chinese, English, science, physics, mathematics
3. Use different symbols to display the tree structure and determine whether there are nodes of the same level and level at the next level.
"Connection. Example:(1) liberal arts; (2) Chinese; (2); (2); (2); (2); (2); (2); (2); (2); (2); (2); (2); (2); (2); (2 );
4. Use different symbols to display the tree structure and determine whether there are any next-level nodes. If yes, the front displays "+". If not
Yes, "-" is displayed in the front, and then you can determine whether there are any nodes of the next level of the same level. If yes, use "Connections" to connect. For example:+ ┃ 文┣ ┣ + 文┃ ┣- ┗---English +-┗--math
The following are four implementation methods:
First:The first method is the simplest. The first method is to implement the first method. The others are then supplemented. // first, the datatable public dataview DRV (string query) {oledbconnection conn = new oledbconnection () is created (); conn. connectionstring = "provider = Microsoft. jet. oledb.4.0; Data Source = D: \ xcrs. mdb "; Conn. open (); oledbdataadapter ADP = new oledbdataadapter (query, Conn); dataset DS = new dataset (); ADP. fill (DS, "BM"); Return Ds. tables ["BM"]. defaultview; Conn. close (); Conn. dispose ();} // The next step is to recursively load the data table // <summary> // recursive display-Treeview effect imitation // call the method: /// DV = DRV ("select * From BM"); // DV. sort = "pid asc"; // createtree (Treeview Control ID, dataview) /// </Summary> /// <Param name = "trvdbbinding"> name of the Treeview control to be bound </param> /// <returns> result </returns> Public void createcomboboxtree (ComboBox trvdbbinding, dataview DV) {datarowview [] arrdrv = DV. findrows (0); // get root data info int tnnew; If (arrdrv. length = 0) return; foreach (datarowview DR in arrdrv) {trvdbbinding. items. add (Dr ["name"]. tostring (); tnnew = convert. toint32 (Dr ["ID"]); createcomboboxtreenode (trvdbbinding, ref tnnew, DV ,"");}} /// <summary> /// recursive display-other controls Treeview effect imitation // tree Connection database ------ subnode /// </Summary> /// <Param name = "tnparent"> parent id </param> // <returns> result </returns> Public void createcomboboxtreenode (ComboBox trvdbbinding, ref int tnparent, dataview DV, string strfill) {datarowview [] arrdrv = DV. findrows (tnparent); // get children data info int tnnew; foreach (datarowview DR in arrdrv) {trvdbbinding. items. add (strfill + Dr ["name"]. tostring (); tnnew = convert. toint32 (Dr ["ID"]); createcomboboxtreenode (trvdbbinding, ref tnnew, DV, strfill + "");}}
Call method:In the form_load event, write: dataview DV = DRV ("select * From BM"); DV. sort = "pid asc"; // Pai Xu createcomboboxtree (this. combobox1, DV );
