C # Move the Treeview Tree node up and down

/// <Summary> /// move up /// </Summary> /// <Param name = "sender"> </param> /// <Param name = "E"> </param> private void tsbmoveup_click (Object sender, eventargs e) {If (TV _tree.selectednode = NULL) {MessageBox. show ("select the node to be moved! "); This. focus (); return;} folder model = new folder (); treenode node = TV _tree.selectednode; // obtain the value model of the selected node. folderid = node. tag. tostring (); Model. theorder = node. name. tostring (); If (node. prevnode = NULL) // if the previous node of the selected node is null, {return;} folder upmodel = new folder (); treenode upnode = node is returned. prevnode; // obtain the upmodel of the previous node of the selected node. folderid = upnode. tag. tostring (); upmodel. theorder = upnode. name; bool Flag = folderoperation. moveup (model, upmodel); // swaps the order numbers of the two nodes if (FLAG) // if the execution is successful {string theorder = node. name; node. name = upnode. name; upnode. name = theorder; treenode newnode = (treenode) node. clone (); // clone the selected node if (node. parent = NULL) {TV _tree.nodes.insert (upnode. index, newnode); // Insert the current node to the previous node of the selected node} else {node. parent. nodes. insert (upnode. index, newnode);} node. remove (); TV _tree.selectedn Ode = newnode;} else {return ;}} /// <summary> /// move down /// </Summary> /// <Param name = "sender"> </param> /// <Param name =" E "> </param> private void tsbmovedown_click (Object sender, eventargs e) {If (TV _tree.selectednode = NULL) {MessageBox. show ("select the node to be moved! "); This. focus (); return;} folder model = new folder (); treenode node = TV _tree.selectednode; // selected node model. folderid = node. tag. tostring (); Model. theorder = node. name. tostring (); If (node. nextnode = NULL) // if the next node is null, {return;} folder downmodel = new folder (); treenode downode = node is returned. nextnode; downmodel. folderid = downode. tag. tostring (); downmodel. theorder = downode. name; bool flag = folderoperation. moveup (model, downmodel); If (FLAG) {string theorder = node. name; node. name = downode. name; downode. name = theorder; treenode newnode = (treenode) downode. clone (); // clone the next node and all its sub-nodes if (node. parent = NULL) {TV _tree.nodes.insert (node. index, newnode); // Insert the value of the next node to the original node} else {node. parent. nodes. insert (node. index, newnode);} downode. remove (); // Delete the next node TV _tree.selectednode = node; // re-select} else {return;} string SQL = string. format ("Update folder set theorder = '{0}' Where folderid = '{1}'", model. theorder, upmodel. folderid); string sql1 = string. format ("Update folder set theorder = '{0}' Where folderid = '{1}'", upmodel. theorder, model. folderid );

/// <Summary> /// expand and collapse nodes /// </Summary> /// <Param name = "sender"> </param> // <param name = "E"> </param> private void tvdocinfo_afterexpand (Object sender, treevieweventargs e) {If (E. node. parent = NULL) {Treeview tree = (Treeview) sender; tree. aftercheck-= new treevieweventhandler (this. tvdocinfo_afterexpand); // Fold other peer nodes treenode parentnode = E. node. parent; If (parentnode! = NULL) {foreach (treenode tn in parentnode. nodes) {If (TN! = E. node) tn. Collapse () ;}} else {foreach (treenode tn in tree. nodes) {If (TN! = E. node) tn. Collapse ();}}}}

Drag a node. You must set the allowdrop attribute of Treeview to true;

Private point position = new point (0, 0); Private void treeview1_itemdrag (Object sender, itemdrageventargs e) {dodragdrop (E. item, dragdropeffects. move);} private void treeviewincludragenter (Object sender, drageventargs e) {If (E. data. getdatapresent (typeof (treenode) E. effect = dragdropeffects. move; else E. effect = dragdropeffects. none;} private void treeviewincludragdrop (Object sender, drageventargs E) {treenode mynode = NULL; If (E. data. getdatapresent (typeof (treenode) {mynode = (treenode) (E. data. getdata (typeof (treenode);} else {MessageBox. show ("error");} position. X = E. x; position. y = E. y; position = tvtype. pointtoclient (position); treenode dropnode = This. tvtype. getnodeat (position); If (functionsui. createquestiondialog ("whether to add" + mynode. text + "mobile" + dropnode. text + "under? ") = Dialogresult. OK) {// 1. The target node is not empty. 2. The target node is not the byte point of the dragged contact. 3. If (dropnode! = NULL & dropnode. parent! = Mynode & dropnode! = Mynode) {treenode dragnode = mynode; // The dragged node is deleted from the original position. Mynode. remove (); // Add the dropnode to the target node. nodes. add (dragnode);} // if the target node does not exist, that is, if the drag position does not exist, place the dragged node under the root node if (dropnode = NULL) {treenode dragnode = mynode; mynode. remove (); tvtype. nodes. add (dragnode );}}}