Learning to use ASP. NET's system. Collections. arraylist class

Arraylist is a dynamic array of. net.
Main members:

 
/* Static Method */arraylist. adapter () // wrap other ilist objects as arraylist and use arraylist. fixedsize () // The package is a fixed-capacity arraylist. readonly () // The package is read-only arraylist. repeat () // create an arraylist/* attribute */capacity // capacity count // number of elements isfixedsize // is it packaged as a fixed capacity based on the specified number of repeated values? Isreadonly // is it encapsulated as read-only? /* Method */Add () // Add addrange () // Add a set binarysearch () // use the binary method to quickly search. Sort the set before searching. If the set is not found, a result is returned.
 

Element values can be of different types, can be repeated, and can be null:

Protected void button#click (Object sender, eventargs e) {arraylist arr = new arraylist (); arr. add ("ABC"); arr. add (1, 123); arr. add (1, 3.14); arr. add (null); arr. add (null); string S = arr [0]. tostring (); int n = (INT) Arr [1]; double F = (double) Arr [2]; textbox1.text = string. concat (S, ",", N, ",", f); // ABC, 123, 3.14 // textbox1.text = string. concat (ARR [0], ",", arr [1], ",", arr [2]); // same as above}
 

Arraylist. Repeat (), addrange () and traversal:

Protected void button#click (Object sender, eventargs e) {arraylist arr1 = arraylist. repeat ("AAA", 3); arraylist arr2 = arraylist. repeat ("BBB", 4); arr1.addrange (arr2); string S1, S2; S1 = S2 = ""; foreach (var x in arr1) {S1 + = x. tostring () + ""; // AAA aaa bbb BBB} For (INT I = 0; I
 

Getrange (), setrange ():

Protected void button#click (Object sender, eventargs e) {arraylist arr1 = new arraylist (6); // specify the capacity arr1.add (1); arr1.add (2); arr1.add (3 ); arr1.add (4); arr1.add (5); arr1.add (6); arraylist arr2 = arr1.getrange (2, 3); string S1 = string. join (",", arr2.toarray (); // 3, 4, 5 arr1.setrange (3, arr2); // The elements in arr2 overwrite the specified location of arr1, arr1 must have a location. String S2 = string. join (",", arr1.toarray (); // 1, 2, 3, 3, 4, 5 textbox1.text = S1 + "\ n" + S2 ;}
 

Flip and sort:

Protected void button#click (Object sender, eventargs e) {arraylist arr = new arraylist (10); // specify the ARR capacity. add (1); arr. add (3); arr. add (5); arr. add (7); arr. add (9); arr. add (2); arr. add (4); arr. add (6); arr. add (8); arr. add (0); arr. reverse (); string S1 = string. join (",", arr. toarray (); // 0, 8, 6, 4, 2, 9, 7, 5, 3, 1 arr. reverse (0, arr. count/2); string S2 = string. join (",", arr. toarray (); // 2, 4, 6, 8, 0, 9, 7, 5, 3, 1 arr. sort (); string S3 = string. join (",", arr. toarray (); // 0, 1, 2, 3, 4, 5, 6, 7, 8, 9 textbox1.text = S1 + "\ n" + S2 + "\ n" + S3 ;}
 

Insert and delete:

 
Protected void button#click (Object sender, eventargs e) {arraylist arr = new arraylist (9); // specify the capacity for (INT I = 0; I
 

Indexof (), lastindexof ():

 
Protected void button#click (Object sender, eventargs e) {char [] chararr = "google ". tochararray (); arraylist arr = new arraylist (chararr); // Its creation parameter can be an icollection string S1 = string. join (",", arr. toarray (); // G, O, O, G, L, E int n1 = arr. indexof ('G'); // 0 int n2 = arr. lastindexof ('G'); // 3 textbox1.text = string. concat (S1, "\ n", N1, "\ n", N2 );}
 

Binarysearch ():

Protected void button#click (Object sender, eventargs e) {string [] strarr = {"one", "two", "three", "four", "five ", "Six", "Seven", "eight", "Nine", "Ten"}; arraylist arr = new arraylist (strarr); arr. sort (); int I = arr. binarysearch ("Nine"); // 3 string STR = string. join (",", arr. toarray (); // eight, five, four, nine, one, seven, six, ten, three, two textbox1.text = string. concat (I, "\ n", STR );}
 

Fixedsize (), readonly (), isfixedsize, isreadonly:

Protected void button#click (Object sender, eventargs e) {arraylist arr = new arraylist (); arr. add ("one"); arr = arraylist. fixedsize (ARR); try {arr. add ("two");} catch (exception ERR) {response. write (err. message);} // The set size is fixed. Finally {textbox1.text = "fixedsize =" + arr. isfixedsize. tostring ();} // fixedsize = true} protected void button2_click (Object sender, eventargs e) {arraylist arr = arraylist. repeat ("000", 3); arr [0] = "AAA"; bool b1 = arr. isreadonly; // false arr = arraylist. readonly (ARR); bool b2 = arr. isreadonly; // true // arr [0] = "BBB"; // if the value is re-assigned, textbox1.text = string is abnormal. concat (B1, "\ n", B2 );}