Using usage C #

2. // Using is used as the namespace indicator
4. Using system;
6. Using system. Collections. Generic;
8. Using system. text;
10. Using system. IO;
14. Namespace statement
16. {
18. // Specify the font class alias as F
20. Using F = system. Drawing. Font;
22. Class Program
24. {
26. Static void main (string [] ARGs)
28. {
30. // Usage of using statement for resource management
32. Using (textwriter W = file. createtext ("E: // test.txt "))
34. {
36. W. writeline (@"Using statement usage: The using statement allowsProgramThe User specifies when the resource object should be released. Resource management statement function ");
38. // Use an alias to instantiate an object
40. F font =New F ("", 12 );
42. W. writeline (font. Name. tostring () + font. Size. tostring ());
44. }
48. // The preceding using statement is equivalent to the following precompiled statement.
50. # If debug
52. Textwriter W = file. createtext ("E: // test.txt ");
54. Try
56. {
58. W. writeline (@"Using statement usage: The using statement allows programmers to specify when the resource object should be released. Resource management statement function ");
60. }
62. Finally
64. {
66. // Standard writing method. The following statement can also be directly written as W. Dispose ()
68. If (W! = NULL) (idisposable) W). Dispose ();
70. }
72. # Endif
76. // You can declare an object in the using statement or declare an object before the using statement, as follows:
78. Textreader r = file. opentext ("E: // test.txt ");
80. Using (r)
82. {
84. String stringd = R. readtoend ();
86. Console. writeline (stringd );
88. }
90. }
92. }
94. }

// Using is used as the namespace indicator using system; using system. collections. generic; using system. text; using system. io; namespace statement {// specify the alias of the font class as f using F = system. drawing. font; Class program {static void main (string [] ARGs) {// usage of using statement to manage resources using (textwriter W = file. createtext ("E: // test.txt") {W. writeline (@ "using statement usage: The using statement allows the programmer to specify when the resource object should be released. Has the resource management statement function "); // uses the alias to instantiate the object F font = new F (" ", 12); W. writeline (font. name. tostring () + font. size. tostring ();} // The preceding using statement is equivalent to the following precompiled statement # If debug textwriter W = file. createtext ("E: // test.txt"); try {W. writeline (@ "using statement usage: The using statement allows the programmer to specify when the resource object should be released. Has the resource management statement function ");} finally {// standard writing method. The following statement can also be directly written as W. Dispose () if (W! = NULL) (idisposable) W ). dispose () ;}# endif // you can declare an object in the using statement or declare an object before the using statement, as follows: textreader r = file. opentext ("E: // test.txt"); Using (r) {string stringd = R. readtoend (); console. writeline (stringd );}}}}

 

My most common problems are:

Using (sqlconnection conn = new sqlconnection (sqlhelper. sqlconnection ))
{
Dataview DV = sqlhelper. executedataset (Conn, commandtype. Text, SQL). Tables [0]. defaultview;
}