A collection of commonly used small functions and methods in c#.net

1. DateTime numeric type System.DateTime currentTime=new System.DateTime(); 1.1 Get the current year, month, day, hour, minute and second currentTime=System.DateTime.Now; 1.2 Get the current year int year = currentTime.Year; 1.3 Get the current month int Month = currentTime.Month; 1.4 Get the current day int day = currentTime.Day; 1.5 Get the current time int hour = currentTime.Hour; 1.6 Get the current minute int minute = currentTime.Minute; 1.7 Get the current second int second = currentTime.Second; 1.8 Get the current millisecond int millisecond = currentTime.Millisecond; (variables are available in Chinese) 2. Int32.Parse (variable) Int32.Parse ("constant") character type is converted into a 32-bit digital type 3. Variable.ToString() character type Convert to string 12345.ToString("n");//Generate 12,345.0012345.ToString("C");//Generate ￥12,345.0012345.ToString("e");//Generate 1.234500e+00412345.ToString(" f4");//Generate 12345.000012345.ToString("x");//Generate 3039 (hexadecimal) 12345.ToString("p");//Generate 1,234,500.00%4, variable .Length digital type takes the string length : Such as: string str="China";int Len = str.Length;//Len is a custom variable, str is the variable name of the string to be tested 5. System.Text.Encoding.Default.GetBytes (variable) word Convert the code to bit code such as: byte[] bytStr = System.Text.Encoding.Default.GetBytes(str); Then you can get the bit length: len = bytStr.Length; 6. System.Text.StringBuilder("") String addition, (is the same with + sign?) For example: System.Text.StringBuilder sb = new System.Text.StringBuilder("");sb.Append("China");sb.Append("People" );sb.Append("Republic");7. Variable.Substring(parameter 1, parameter 2); intercept part of the string, parameter 1 is the starting digit from the left, and parameter 2 is the number of digits to intercept. For example: string s1 = str.Substring(0,2); 8. String user_IP=Request.ServerVariables["REMOTE_ADDR"].ToString(); Get the remote user's IP address 9. Get the remote user's real IP address through the proxy server: if(Request.ServerVariables["HTTP_VIA"]!=null){stringuser_IP=Request.ServerVariables["HTTP_X_FORWARDED_FOR"].ToString();}else{stringuser_IP=Request.ServerVariables["REMOTE_ADDR"].ToString();}10 , Session["variable"]; access Session value; for example, assignment: Session["username"]="Bush"; value: Object objName=Session["username"];String strName=objName.ToString() ; Clear: Session.RemoveAll(); 11. String str=Request.QueryString["Variable"]; Use hyperlink to transfer variables. For example, create a hyperlink in any page: Click to get the value in the Edit.aspx page: String str=Request.QueryString["fdid"];12 , DOC object.CreateElement("New node name"); Create a new node of the XML document 13. Parent node.AppendChild (child node); Add the newly created child node to the parent node of the XML document 14. Parent node.RemoveChild (node) ;Delete node 15, ResponseResponse.Write("string");Response.Write(variable);Output to the page. Response.Redirect("URL address"); jump to the page specified by the URL 16. char.IsWhiteSpce (string variable, number of digits) - logical type to check whether the specified position is a null character; such as: string str="Chinese People" ;Response.Write(char.IsWhiteSpace(str,2)); //The result is: True, the first character is 0, and 2 is the third character. 17. char.IsPunctuation('Character')--Logical check whether the character is a punctuation mark, such as: Response.Write(char.IsPunctuation('A'));//Return: False18, (int)'Character' returns the character Convert to a number, look up the code point, pay attention to the single quotes. For example: Response.Write((int)'中');//The result is the Chinese character code: 2001319. The (char) code converts numbers into characters and checks the characters represented by the code. For example: Response.Write((char)22269);//Return the character "国". 20. Trim() clears the spaces before and after the string 21. String variable.Replace("substring", "replace with") string replacement such as: string str="China";str=str.Replace("国" ,"central");//Replace the national character with the central character Response.Write(str);//The output result is "central" Another example: (This is very practical) string str="This is