Blog that contains articles about new technologies related or not with programming. I will describe and solves some problems that I encounter in my career. ASP .NET, AJAX, Javascript, C++, C# and SQL are some of the subjects that will appear.
07 March 2012
array in javascript
<p id="div_p"></p>
var array = ["S", "V", "B"];
document.getElementById("div_p").innerHTML = array
var arrIDs=new Array();
arrIDs.push(e);
document.getElementById("div_p").innerHTML=arrIDs.join(',');
var arr = new Array(3);
arr[0] = "a";
arr[1] = "b";
arr[2] = "c";
var array1 = new Array("S", "V", "B");
//for object
var person = {firstName:"John", lastName:"Doe", age:46};
At position 2, add the new items, and remove 1 item:
The result of fruits will be:
var array = ["S", "V", "B"];
document.getElementById("div_p").innerHTML = array
var arrIDs=new Array();
arrIDs.push(e);
document.getElementById("div_p").innerHTML=arrIDs.join(',');
var arr = new Array(3);
arr[0] = "a";
arr[1] = "b";
arr[2] = "c";
var array1 = new Array("S", "V", "B");
//for object
var person = {firstName:"John", lastName:"Doe", age:46};
At position 2, add the new items, and remove 1 item:
var fruits = ["Banana", "Orange", "Apple", "Mango"];
fruits.splice(2, 1, "Lemon", "Kiwi");
The result of fruits will be:
Banana,Orange,Lemon,Kiwi,Mango
31 January 2012
timer countdown in asp.net
Label4.Text = "00";
Label5.Text = "02";
Label6.Text = "00";
if (Label6.Text == "00" || Label6.Text == "0")
{
if (Label5.Text == "00" || Label5.Text == "0")
{
if (Label4.Text == "00" || Label4.Text == "0")
{
Timer1.Enabled = false;
}
else
{
Label4.Text = (Convert.ToInt32(Label4.Text) - 1).ToString();
if (Label4.Text.Trim().Length == 1)
Label4.Text = "0" + Label4.Text;
Label5.Text = "60";
}
}
else
{
Label5.Text = (Convert.ToInt32(Label5.Text) - 1).ToString();
if (Label5.Text.Trim().Length == 1)
Label5.Text = "0" + Label5.Text;
Label6.Text = "60";
}
}
else
{
Label6.Text = (Convert.ToInt32(Label6.Text) - 1).ToString();
if (Label6.Text.Trim().Length == 1)
Label6.Text = "0" + Label6.Text;
}
Label5.Text = "02";
Label6.Text = "00";
if (Label6.Text == "00" || Label6.Text == "0")
{
if (Label5.Text == "00" || Label5.Text == "0")
{
if (Label4.Text == "00" || Label4.Text == "0")
{
Timer1.Enabled = false;
}
else
{
Label4.Text = (Convert.ToInt32(Label4.Text) - 1).ToString();
if (Label4.Text.Trim().Length == 1)
Label4.Text = "0" + Label4.Text;
Label5.Text = "60";
}
}
else
{
Label5.Text = (Convert.ToInt32(Label5.Text) - 1).ToString();
if (Label5.Text.Trim().Length == 1)
Label5.Text = "0" + Label5.Text;
Label6.Text = "60";
}
}
else
{
Label6.Text = (Convert.ToInt32(Label6.Text) - 1).ToString();
if (Label6.Text.Trim().Length == 1)
Label6.Text = "0" + Label6.Text;
}
25 January 2012
Tooltip for dropdownlist items
It is common in most web pages that whole text in dropdown lists cannot be seen due to width limitation. One solution for this would be adding tooltip for the dropdown, so that when selecting a value from dropdown, whole text will be appear as a tooltip. For most of browsers implementing tooltip on dropdown control is not a big deal. We can simply add tooltip text with 'title' attribute. C# implementation for this would be as follows
public void SetToolTip(DropDownList ddl)
{
if (ddl.Items.Count > 0)
{
foreach (ListItem item in ddl.Items)
{
item.Attributes.Add("Title", item.Text);
}
}
}
public void SetToolTip(DropDownList ddl)
{
if (ddl.Items.Count > 0)
{
foreach (ListItem item in ddl.Items)
{
item.Attributes.Add("Title", item.Text);
}
}
}
21 January 2012
change the database name in sqlserver using query
Supported in SQL Server 2000 and 2005
exec sp_renamedb 'databasename' , 'newdatabasename'
Supported in SQL Server 2005 and later version
ALTER DATABASE 'databasename' MODIFY NAME = 'newdatabasename'
select DB_NAME()
select name from sys.databases
exec sp_renamedb 'databasename' , 'newdatabasename'
Supported in SQL Server 2005 and later version
ALTER DATABASE 'databasename' MODIFY NAME = 'newdatabasename'
select DB_NAME()
select name from sys.databases
07 January 2012
Naming conventions in .net
Pascal case
The first letter in the identifier and the first letter of each subsequent concatenated word are capitalized.Example:BackColor, DataSet
Camel case
The first letter of an identifier is lowercase and the first letter of each subsequent concatenated word is capitalized.Example:numberOfDays, isValid
Uppercase
All letters in the identifier are capitalized.Example:ID, PI
1). Private Variables: _strFirstName, _dsetEmployees
2). Local Variables: strFirstName, dsetEmployees
3). Namespace:(Pascal) System.Web.UI, System.Windows.Forms
4). Class Naming:(Pascal) FileStream, Button
5). Interface Naming:(Pascal) IServiceProvider, IFormatable
6). Parameter Naming:(Camel) pTypeName, pNumberOfItems
7). Method Naming:(Pascal) RemoveAll(), GetCharAt()
7). Method Parameters:(Camel) void SayHello(string name)....
8). Property / Enumerations Naming:(Pascal) BackColor, NumberOfItems
8). Property / Enumerations Naming:(Pascal) BackColor, NumberOfItems
9). Event Naming:(Pascal) public delegate void MouseEventHandler(object sender, MouseEventArgs e);
10). Exception Naming: catch (Exception ex){ }
11). Constant Naming: AP_WIN, CONST
Some Coding Standards in .net
1. Use Meaningful, descriptive words to name variables. Do not use abbreviations.
Good:
string address
int salary
string address
int salary
Not Good:
string name
string addr
int sal
2. Do not use single character variable names like i, n, s etc. Use names like index, temp
variable 'i' is used for for iterations in loops
Ex: for ( int i = 0; i < count; i++ ){....}
3. Do not use underscores (_) for local variable names. But member variables must be prefixed with underscore (_)
4. Prefix boolean variables, properties and methods with “is” or similar prefixes.
Ex: private bool _isFinished
5. File name should match with class name.
Ex: for the class HelloWorld, the file name should be helloworld.cs (or, helloworld.vb)
6. Keep private member variables, properties and methods in the top of the file and public members in the bottom.
7. Use String.Empty instead of “”
Ex: txtMobile= String.Empty;
8. 8. Avoid having very large files. If a single file has more than 1000 lines of code, it is a good candidate for refactoring. Split them logically into two or more classes.
9. Use StringBuilder class instead of String when you have to manipulate string objects in a loop. The String object works in weird way in .NET. Each time you append a string, it is actually discarding the old string object and recreating a new object, which is a relatively expensive operations.
factorial of number in console applications
int count = 1;
Console.Write("Enter Number for factorial: ");
int number = Convert.ToInt32(Console.ReadLine());
for (int i = 1; i <= number; i++)
{
count = count * i;
}
Console.Write(count);
Console.Read();
or
public static long numfact(long n)
{
if (n <= 1)
return 1;
else
return n * numfact(n - 1);
}
Console.Write(numfact(5));
Console.Write("Enter Number for factorial: ");
int number = Convert.ToInt32(Console.ReadLine());
for (int i = 1; i <= number; i++)
{
count = count * i;
}
Console.Write(count);
Console.Read();
or
public static long numfact(long n)
{
if (n <= 1)
return 1;
else
return n * numfact(n - 1);
}
Console.Write(numfact(5));
palindrome in console applications
string str = string.Empty;
Console.WriteLine("Enter a String");
string s = Console.ReadLine();
int i = s.Length;
for (int j = i - 1; j >= 0; j--)
{
str = str + s[j];
}
if (str == s)
Console.WriteLine(s + " is palindrome");
else
Console.WriteLine(s + " is not a palindrome");
Console.WriteLine("Enter a String");
string s = Console.ReadLine();
int i = s.Length;
for (int j = i - 1; j >= 0; j--)
{
str = str + s[j];
}
if (str == s)
Console.WriteLine(s + " is palindrome");
else
Console.WriteLine(s + " is not a palindrome");
06 January 2012
group by and row no in sql
SELECT ROW_NUMBER() OVER (ORDER BY ColumnName1) As SrNo, ColumnName1, ColumnName2 FROM TableName
SELECT DENSE_RANK() OVER (ORDER BY ColumnName1) As SrNo, ColumnName1, ColumnName2 FROM TableName
select top 1 ROW_NUMBER()over(orderby col1)as slno,* from tbl1 orderby slno desc
SELECT DENSE_RANK() OVER (ORDER BY ColumnName1) As SrNo, ColumnName1, ColumnName2 FROM TableName
select top 1 ROW_NUMBER()over(orderby col1)as slno,* from tbl1 orderby slno desc
sql syntaxes
Select Statement
SELECT "column_name" FROM "table_name"
Distinct
SELECT DISTINCT "column_name" FROM "table_name"
Where
SELECT "column_name" FROM "table_name" WHERE "condition"
And/Or
SELECT "column_name" FROM "table_name" WHERE "simple condition" {[AND|OR] "simple condition"}+
In
SELECT "column_name" FROM "table_name" WHERE "column_name" IN ('value1', 'value2', ...)
Between
SELECT "column_name" FROM "table_name" WHERE "column_name" BETWEEN 'value1' AND 'value2'
Like
SELECT "column_name" FROM "table_name" WHERE "column_name" LIKE {PATTERN}
Order By
SELECT "column_name" FROM "table_name" [WHERE "condition"] ORDER BY "column_name" [ASC,DESC]
Count
SELECT COUNT("column_name") FROM "table_name"
Group By
SELECT "column_name1", SUM("column_name2") FROM "table_name" GROUP BY "column_name1"
Having
SELECT "column_name1", SUM("column_name2") FROM "table_name" GROUP BY "column_name1" HAVING (arithematic function condition)
Create Table Statement
CREATE TABLE "table_name" ("column 1" "data_type_column_1", "column 2" "data_type_for_column_2",.... )
Drop Table Statement
DROP TABLE "table_name"
Truncate Table Statement
TRUNCATE TABLE "table_name"
Insert Into Statement
INSERT INTO "table_name" ("column1", "column2", ...) VALUES ("value1", "value2", ...)
Update Statement
UPDATE "table_name" SET "column_1" = [new value] WHERE {condition}
Delete From Statement
DELETE FROM "table_name" WHERE {condition}
select--scalar--string, update,insert,delete--nonquery--int
Ref:
http://www.1keydata.com/sql/sql-syntax.html
http://www.sqlcommands.net/
SELECT "column_name" FROM "table_name"
Distinct
SELECT DISTINCT "column_name" FROM "table_name"
Where
SELECT "column_name" FROM "table_name" WHERE "condition"
And/Or
SELECT "column_name" FROM "table_name" WHERE "simple condition" {[AND|OR] "simple condition"}+
In
SELECT "column_name" FROM "table_name" WHERE "column_name" IN ('value1', 'value2', ...)
Between
SELECT "column_name" FROM "table_name" WHERE "column_name" BETWEEN 'value1' AND 'value2'
Like
SELECT "column_name" FROM "table_name" WHERE "column_name" LIKE {PATTERN}
Order By
SELECT "column_name" FROM "table_name" [WHERE "condition"] ORDER BY "column_name" [ASC,DESC]
Count
SELECT COUNT("column_name") FROM "table_name"
Group By
SELECT "column_name1", SUM("column_name2") FROM "table_name" GROUP BY "column_name1"
Having
SELECT "column_name1", SUM("column_name2") FROM "table_name" GROUP BY "column_name1" HAVING (arithematic function condition)
Create Table Statement
CREATE TABLE "table_name" ("column 1" "data_type_column_1", "column 2" "data_type_for_column_2",.... )
Drop Table Statement
DROP TABLE "table_name"
Truncate Table Statement
TRUNCATE TABLE "table_name"
Insert Into Statement
INSERT INTO "table_name" ("column1", "column2", ...) VALUES ("value1", "value2", ...)
Update Statement
UPDATE "table_name" SET "column_1" = [new value] WHERE {condition}
Delete From Statement
DELETE FROM "table_name" WHERE {condition}
select--scalar--string, update,insert,delete--nonquery--int
Ref:
http://www.1keydata.com/sql/sql-syntax.html
http://www.sqlcommands.net/
02 January 2012
C# Features not in Java
•No automatic fall-through from one case block to the next
•Strongly-typed enums
•By reference calls are explicit at caller AND callee
•Method overrides are explicit
•Supports versioning
•Structs (value types)
•Integrated support for properties and events
•Can still use pointers with RAD language
Can share data and use functionality with components written in many different languages
Development tools and Documentation
Server-side is well supported by both Java and .NET IDEs
On the client-side .NET IDEs benefit from the fact that .NET CF is so close to .NET (With Java there are separate IDEs for desktop and mobile application development)
Compatibility problems between Java vendors
Java IDEs are slow!
C# is a richer/more complex language than Java
Both Java and .NET have well documented API
Web service documentation
.NET - MSDN
Java – Google
Support for encryption of web services
.Net CF: HTTPS and SOAP extensions
J2ME: HTTPS, but only in CDC & MIDP 2.0
C# and JAVA
CSharp and JAVA are two different Object Oriented Languages , both have some similarities and differences also . The Csharp and JAVA derived from their own single ancestor Class "Object". All Classes in C# are descended from System.Object Class and in JAVA all classes are subclasses of java.lang.Object Class.
Both C# and JAVA have their own runtime environments . C# source codes are compiled to Microsoft Intermediate Language (MSIL) and during the execution time runs it with the help of runtime environments - Common Language Runtime (CLR). Like that JAVA source codes are compiled to Java Byte Code and during the execution time runs it with the help of runtime environments - Java Virtual Machine (JVM). Both CSharp and JAVA supports native compilation via Just In Time compilers.
More over both C# and JAVA have their own Garbage Collector. In the case of keywords comparison some keywords are similar as well as some keywords are different also. The following are the examples of few similar and different keywords.
Similar Keywords examples
class , new , if , case , for , do , while , continue , int , char , double , null
joins example
table1 table2
col1 col2 col3 col4
1 a 1 a
2 b 2 b
null c 3 c
4 null null d
inner join result:
col1 col2 col3 col4
1 a 1 a
2 b 2 b
left outer join result:
col1 col2 col3 col4
1 a 1 a
2 b 2 b
null c null null
4 null null null
full outer join result:
col1 col2 col3 col4
1 a 1 a
2 b 2 b
null c null null
4 null null null
null null 3 c
null null null d
col1 col2 col3 col4
1 a 1 a
2 b 2 b
null c 3 c
4 null null d
inner join result:
col1 col2 col3 col4
1 a 1 a
2 b 2 b
left outer join result:
col1 col2 col3 col4
1 a 1 a
2 b 2 b
null c null null
4 null null null
full outer join result:
col1 col2 col3 col4
1 a 1 a
2 b 2 b
null c null null
4 null null null
null null 3 c
null null null d
27 December 2011
ddl in js
opt=document.createElement("OPTION");
document.getElementById('ddlPages').options.add(opt);
opt.text=cnt-1;
opt.value=cnt-1;
document.getElementById('ddlPages').options.add(opt);
opt.text=cnt-1;
opt.value=cnt-1;
16 December 2011
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