(C #) comprehensive example of the Treeview Control

Use the Treeview control to create a tree. The program has the function of saving text and binary.

Using system; using system. collections. generic; using system. componentmodel; using system. data; using system. drawing; using system. LINQ; using system. text; using system. windows. forms; using system. io; using system. text. regularexpressions; using system. runtime. serialization. formatters. binary; // knowledge point: // applications of the Treeview control: add, modify, and delete nodes // get the value of the current node and parent node // select an event for the response node // namespace ch0602 _ Student Score _ binary file _ {public partial class Frmgrade: FORM {public frmgrade () {initializecomponent ();} private void btnaddsc_click (Object sender, eventargs e) {If (cbotype. selectedindex = 0) {// Add a school node and specify it as the current node if (txtnamesc. text. length> 0) {treenode node = tvsc. nodes. add (txtnamesc. text); tvsc. selectednode = node;} else MessageBox. show ("Please specify the school name");} else {If (tvsc. selectednode = NULL | tvsc. selectednode. level> = 1) Message Box. show ("select a school first, and then create a class node"); else {// Add a class node, and expand the school node if (txtnamesc. text. length> 0) {tvsc. selectednode. nodes. add (txtnamesc. text); tvsc. selectednode. expand ();} else MessageBox. show ("Please specify the class name") ;}} private void btnaddstud_click (Object sender, eventargs e) {If (tvsc. selectednode = NULL | tvsc. selectednode. level! = 1) {MessageBox. show ("Please specify the class"); return;} string sname = tvsc. selectednode. parent. text; string cname = tvsc. selectednode. text; Student stud = new student (sname, cname); stud. no = txtno. text; stud. name = txtname. text; stud. sex = cbosex. text; stud. birth = datetime. parse (dtpbirth. text); stud. grade = int. parse (txtgrade. text); stud. ADDR = txtaddr. text; treenode node = tvsc. selectednode. nodes. add (stud. n O); // bind the data node to the added node. tag = stud; // expand the class node tvsc. selectednode. expand ();} private void tvsc_afterselect (Object sender, treevieweventargs e) {// display the content of the current node if (tvsc. selectednode! = NULL & tvsc. selectednode. Level = 2 & tvsc. selectednode. Tag! = NULL) {student stud = (student) tvsc. selectednode. tag; lbostudent. items. add (stud. tostring (); txtno. TEXT = stud. no; txtname. TEXT = stud. name; cbosex. TEXT = stud. sex; dtpbirth. TEXT = stud. birth. tostring (); txtgrade. TEXT = stud. grade. tostring (); txtaddr. TEXT = stud. ADDR ;}} private void tvsc_afterselect (Object sender, treevieweventargs e) {// display the content of the current node if (tvsc. selectednode! = NULL & tvsc. selectednode. Level = 2 & tvsc. selectednode. Tag! = NULL) {student stud = (student) tvsc. selectednode. tag; lbostudent. items. add (stud. tostring (); txtno. TEXT = stud. no; txtname. TEXT = stud. name; cbosex. TEXT = stud. sex; dtpbirth. TEXT = stud. birth. tostring (); txtgrade. TEXT = stud. grade. tostring (); txtaddr. TEXT = stud. ADDR ;}} private void cbotype_selectedindexchanged (Object sender, eventargs e) {txtnamesc. clear ();} private void btnmodstud_click (OB Ject sender, eventargs e) {If (tvsc. selectednode = NULL | tvsc. selectednode. level! = 2) {MessageBox. show ("Please specify student"); return;} string sname = tvsc. selectednode. parent. parent. text; string cname = tvsc. selectednode. parent. text; Student stud = new student (sname, cname); stud. no = txtno. text; stud. name = txtname. text; stud. sex = cbosex. text; stud. birth = datetime. parse (dtpbirth. text); stud. grade = int. parse (txtgrade. text); stud. ADDR = txtaddr. text; // modify the node information tvsc. selectednode. TEXT = s Tud. no; // modify the bound data of the node tvsc. selectednode. tag = stud;} private void btndelstud_click (Object sender, eventargs e) {// Delete the node data tvsc. selectednode. remove () ;}// read the text file and generate the tree structure private void mifileread_click (Object sender, eventargs e) {// display the Open File Dialog Box openfiledialog dlgopen = new openfiledialog (); if (dlgopen. showdialog ()! = Dialogresult. OK) return; // open the file in the specified file and encoding format and prepare to read streamreader sr = new streamreader (dlgopen. filename, encoding. default); tvsc. nodes. clear (); string pattern = @ "\ s *, \ s * | \ s +"; // "\ s" indicates space, "\ s *" indicates zero or multiple spaces, and "\ s +" indicates one or more spaces. String sname0 = "", cname0 = ""; // read a line of text string line; string [] fields; while (line = sr. readline ())! = NULL) {// fields = line. split ('', '\ t'); fields = RegEx. split (line, pattern); string sname = Fields [0]; string cname = Fields [1]; Student stud = new student (sname, cname); stud. no = Fields [2]; stud. name = Fields [3]; stud. sex = Fields [4]; stud. birth = convert. todatetime (fields [5]); stud. grade = int. parse (fields [6]); stud. ADDR = Fields [7]; // if the school name changes, add the school node if (sname! = Sname0) {tvsc. selectednode = tvsc. nodes. Add (sname); sname0 = sname;} // if the class name changes, add the class node if (cname! = Cname0) {// adjust the current node if (tvsc. selectednode. level = 1) tvsc. selectednode = tvsc. selectednode. parent; tvsc. selectednode = tvsc. selectednode. nodes. add (cname); cname0 = cname;} // Add the student node treenode node = tvsc. selectednode. nodes. add (stud. no); node. tag = stud;} // close the file Sr. close () ;}// traverse the tree structure and write the text file private void mifilewrite_click (Object sender, eventargs e) {// display the save file dialog box savefiledialog dlgsave = new SA Vefiledialog (); If (dlgsave. showdialog ()! = Dialogresult. OK) return; // specify the file and encoding format to open the specified file. Prepare to write streamwriter Sw = new streamwriter (dlgsave. filename, false, encoding. default); // traverses the tree structure and writes the writetxtfile (SW, tvsc. nodes); // close the SW file. close () ;}// recursively traverse all nodes in a tree. Private void writetxtfile (streamwriter SW, treenodecollection nodes) {foreach (treenode node in nodes) {If (node. level = 2) {student stud = node. tag as student; string line = string. form At ("{0} \ t {1} \ t {2} \ t {3} \ t {4} \ t {5: yyyy-mm-dd} \ t {6} \ t {7} ", stud. sname, stud. cname, stud. no, stud. name, stud. sex, stud. birth, stud. grade, stud. ADDR); Sw. writeline (line);} If (node. nodes. count> 0) writetxtfile (SW, node. nodes) ;}} private void mifilereadbin_click (Object sender, eventargs e) {openfiledialog dlgopen = new openfiledialog (); If (dlgopen. showdialog ()! = Dialogresult. OK) return; filestream FS = new filestream (dlgopen. filename, filemode. open, fileaccess. read); tvsc. nodes. clear (); // create a read stream Class BR binaryreader BR = new binaryreader (FS); // initialize the variable string sname0 = "", cname0 = ""; // The file Pointer Points to the file header BR. basestream. seek (0, seekorigin. begin); // read cyclically until the file Pointer Points to the end of the file while (BR. basestream. position <br. basestream. length) {// read the student stud = new student (); s by field Tud. sname = BR. readstring (); stud. cname = BR. readstring (); stud. no = BR. readstring (); stud. name = BR. readstring (); stud. sex = BR. readstring (); stud. birth = convert. todatetime (BR. readstring (); stud. grade = BR. readint32 (); stud. ADDR = BR. readstring (); // Add to the Tree node // if the school name changes, add the school node if (stud. sname! = Sname0) {tvsc. selectednode = tvsc. nodes. add (stud. sname); sname0 = stud. sname;} // if the class name changes, add the class node if (stud. cname! = Cname0) {// adjust the current node if (tvsc. selectednode. level = 1) tvsc. selectednode = tvsc. selectednode. parent; tvsc. selectednode = tvsc. selectednode. nodes. add (stud. cname); cname0 = stud. cname;} // Add the student node treenode node = tvsc. selectednode. nodes. add (stud. no); node. tag = stud;} BR. close (); FS. close ();} private void mifilewritebin_click (Object sender, eventargs e) {// display the save file dialog box savefiledialog dlgsave = new Savefiledialog (); If (dlgsave. showdialog ()! = Dialogresult. OK) return; // create a Write File stream FS filestream FS = new filestream (dlgsave. filename, filemode. create, fileaccess. write); // create a write stream class BW binarywriter BW = new binarywriter (FS); // traverse the tree structure and write the text file writebinfile (BW, tvsc. nodes); // close the write stream class and file stream BW. close (); FS. close () ;}// recursively traverse all nodes in a tree. Private void writebinfile (binarywriter BW, treenodecollection nodes) {foreach (treenode node in nodes) {If (node. level = 2) {student stud = node. tag as student; BW. write (stud. sname); BW. write (stud. cname); BW. write (stud. no); BW. write (stud. name); BW. write (stud. sex); BW. write (stud. birth. tostring ("yyyy-mm-dd"); BW. write (stud. grade); BW. write (stud. ADDR);} If (node. nodes. count> 0) writebinfile (BW, node. nodes) ;}} private void mifilereadbin2_click (Object sender, eventargs e) {openfiledialog dlgopen = new openfiled Ialog (); If (dlgopen. showdialog ()! = Dialogresult. OK) return; filestream FS = new filestream (dlgopen. filename, filemode. open, fileaccess. read); binaryreader BR = new binaryreader (FS); tvsc. nodes. clear (); // initialization variable string sname0 = "", cname0 = ""; // The file Pointer Points to the file header FS. seek (0, seekorigin. begin); // read cyclically until the file Pointer Points to the end of the file while (FS. position <FS. length) {// read the records of each student by field int length = BR. readint32 (); byte [] buffer = new byte [length]; buffer = BR. rea Dbytes (length); Student stud = (student) bytestoobject (buffer); // Add to the Tree node // if the school name changes, add the school node if (stud. sname! = Sname0) {tvsc. selectednode = tvsc. nodes. add (stud. sname); sname0 = stud. sname;} // if the class name changes, add the class node if (stud. cname! = Cname0) {// adjust the current node if (tvsc. selectednode. level = 1) tvsc. selectednode = tvsc. selectednode. parent; tvsc. selectednode = tvsc. selectednode. nodes. add (stud. cname); cname0 = stud. cname;} // Add the student node treenode node = tvsc. selectednode. nodes. add (stud. no); node. tag = stud;} BR. close (); FS. close ();} private void mifilewritebin2_click (Object sender, eventargs e) {// display the save file dialog box savefiledialog dlgsave = new Savefiledialog (); If (dlgsave. showdialog ()! = Dialogresult. OK) return; // create a Write File stream FS filestream FS = new filestream (dlgsave. filename, filemode. create, fileaccess. write); binarywriter BW = new binarywriter (FS); // traverses the tree structure and writes the writebinfile2 (BW, tvsc. nodes); // close the write stream class and file stream BW. close (); FS. close ();} private void writebinfile2 (binarywriter BW, treenodecollection nodes) {foreach (treenode node in nodes) {If (node. level = 2) {student stud = node. tag as student; byte [] buffer = objecttobytes (stud); BW. write (buffer. length); BW. write (buffer);} If (node. nodes. count> 0) writebinfile2 (BW, node. nodes) ;}// object serialized as a byte array public static byte [] objecttobytes (Object OBJ) {memorystream MS = new memorystream (); byte [] bytes = NULL; try {// serialize binaryformatter formatter = new binaryformatter (); formatter. serialize (MS, OBJ); bytes = Ms. toarray ();} catch (exception e) {Throw new exception (E. tostring ();} finally {Ms. close ();} return bytes;} // deserialization of the byte array into the object public static object bytestoobject (byte [] bytes) {memorystream MS = new memorystream (bytes ); object OBJ = new object (); try {// deserialization Ms. position = 0; binaryformatter formatter = new binaryformatter (); OBJ = formatter. deserialize (MS);} catch (exception e) {Throw new exception (E. tostring ();} finally {Ms. close ();} return OBJ;} private void miclear_click (Object sender, eventargs e) {tvsc. nodes. clear ();}}}

The following is the definition of a class.

Using system; using system. collections. generic; using system. LINQ; using system. text; namespace ch0602 _ Student Score _ binary file _ {[serializable] public class student {Public String sname {Get; set;} Public String cname {Get; set ;} public String no {Get; set;} public string name {Get; set;} Public String sex {Get; set;} public datetime birth {Get; set ;} public int grade {Get; set;} Public String ADDR {Get; set;} public student () {} public student (string sname, string cname) {sname = sname; cname = cname;} public new string tostring () {return string. format ("{0 }:{ 1}, {2}, {3: yyyy-mm-dd}, {4}, {5}", no, name, sex, birth, grade, ADDR );}}}