Tuesday, May 30, 2006
Microsoft TechEd 2006 - Chennai
Hurry up!!!!!
Visit here to know more about TechEd 2006.
Thursday, November 10, 2005
Microsoft training workshops in Chennai
Please look into the below link:
http://www.microsoft.com/india/learning/cplsoffering.aspx
Monday, August 29, 2005
Converting Class Array to DataTable
private DataTable dtTemp;
private static void FillData(PropertyInfo[] properties, DataTable dt, Object o)
{
DataRow dr = dt.NewRow();
foreach(PropertyInfo pi in properties)
dr[pi.Name] = pi.GetValue(o, null);
dt.Rows.Add(dr);
}
//All the Properties for the class array are converted to columns. We can always add a
//condition to include required columns alone.
private static DataTable CreateDataTable(PropertyInfo[] properties)
{
DataTable dt = new DataTable();
DataColumn dc = null;
foreach(PropertyInfo pi in properties)
{
dc = new DataColumn();
dc.ColumnName = pi.Name;
dc.DataType = pi.PropertyType;
dt.Columns.Add(dc);
}
return dt;
}
public static DataTable ConvertToDataTable(Object[] array)
{
PropertyInfo[] properties = array.GetType().GetElementType().GetProperties();
DataTable dt = CreateDataTable(properties);
if (array.Length != 0)
{
foreach(object o in array)
FillData(properties, dt, o);
}
return dt;
}
//Call like this
//Convert the Class Object Array to DataTable
dtTemp = ConvertToDataTable(clsData);
Monday, May 23, 2005
Regular Expression Internals - II
Continuing with my previous article of "Regular Expression Internals - Part I" at
http://www.codeproject.com/useritems/RegEx.asp, where I discussed about the Regex engine, how it backtracks I am discussing on how to frame an expression logically with few examples.
How to formulate a RegularExpression?
Before we actually enter into formulating a regular expression, we will take a look into few concepts like what are characters, special characters and some of other concepts with examples.
The very simplest pattern matched by a regular expression is a literal character or a sequence of literal characters. Anything in the target text that consists of exactly those characters in exactly the order listed will match. A lower case character is not identical with its upper case version, and vice versa. A space in a regular expression, by the way, matches a literal space in the target.
For instance:
Criteria: /a/
"An institute has posted guidance that protects against a reported vulnerability in all versions of
software that could allow a Web site visitor to view secured content by using specially crafted
requests to a Web server"
Criteria: /Web/"An institute has posted guidance that protects against a reported vulnerability in all versions of
software that could allow a Web site visitor to view secured content by using specially crafted
requests to a Web server".- Escape Characters:
Special characters as we mentioned above has special meanings to regular expressions. Any Special characters (like *, \) can be matched, but to do so we must prefix it with the backslash character (this includes matching a backslash character itself: to match a backslash in the target, your regular expression should include "\\").
For instance: /.*/
- Positioning Characters:
To mark the beginning and end of a line, two special characters are used: caret (^) and dollarsign ($). The .(Period) is a wildcard character, which means it can represent any character(s).
For instance:
Criteria: /^Web/
"An institute has posted guidance that protects against a reported vulnerability in all versions of
software that could allow a Web site visitor to view secured content by using specially crafted
requests to a Web server".
Criteria: /Web$/"An institute has posted guidance that protects against a reported vulnerability in all versions of
software that could allow a Web site visitor to view secured content by using specially crafted
requests to a Web server".Criteria: /.a/"An institute has posted guidance that protects against a reported vulnerability in all versions of
software that could allow a Web site visitor to view secured content by using specially crafted
requests to a Web server".
- Characters Classes and Negation:
Character classes consists of set of square brackets ([]) and Range (-) symbol. The negation is the caret (^) symbol within square brackets.
Instead of supplying only a single character, we can include a pattern in a regular expression that matches any of a set of characters. A set of characters can be given as a sample list inside square brackets.
For instance:
Criteria: /[abcde]/ will match any single lowercase vowel.
For letter or number ranges we may also use only the first and last letter of a range, with a Range (-) in the middle.
For instance:
Criteria: /[A-Za-z0-9]/
This will match any lowercase or uppercase of the alphabets or any numerals from 0 to 9.
Negation in this context refers to everything not included in the listed character set is matched.
For instance:
Criteria: /[^a-e]in]/"An institute has posted guidance that protects against a reported vulnerability in all versions of
software that could allow a Web site visitor to view secured content by using specially crafted
requests to a Web server".Till now we looked into basics of Regular expressions, what is metacharacters, how to formulate an expressions. Now, we will see couple of examples on how to make real time expressions.
- Website URL:
^(((hH?)(tT?)(tT?)(pP?)(sS?))://)?(www.[a-zA-Z0-9].)[a-zA-Z0-9-.]+.[a-zA-Z]*$
The above expression accepts any URL with or without http/https, and output as given below:
a) http://www.aaa.com
b) https://www.ddd.sds
c) www.abc.co.in
Here, the end-user can type the URL in caps or in lower letters. And moreover, the end-user may need the URL with ?http? or may not need the ?http?. Based on this logic, the logical grouping of the expression has to be made. So we have to formulate http/https part of the expression separately and the URL part of the expression separately.
Ø To mark the beginning of expression string, '^' symbol is used and '$' for end of expression string.
Ø '(...)' is used for logical grouping of part of an expression. Taking the protocol part, we have '(hH?)', where the '' means alternation, and the expression returns 'h', 'H'. And '?' means 0 or 1 of previous expression. That is, '(hH?)' returns either 'h' or 'H'. Like this way, the expression evaluates for other letters too in 'http / https'.
Ø Then coming to the URL part i.e. '(www.[a-zA-Z0-9].)', the end-user can type 'www' or any letters from a-z (caps or small) or any numerals. Following the www portion, the domain, .com, .org must also be with same constraint
Ø Finally, we are left with joining the protocol and URL. A '?' must be placed in between both the expressions, which implies that either true or false of previous expression, i.e. a full URL can contain a protocol or need not have to contain a protocol.
- Validating a Number:
^([1-9][1-9]d100)$
The above expression matches whole numbers from 1-100 and output as given below:
a) 1
b) 50
c) 100
Ø As usual to mark the beginning of expression, ?^? symbol is used and ?$? for end of expression.
Ø ?[...]? is used for explicit set of characters to match, i.e. for e.g. a[bB]c -> abc, aBc.
Ø So, for first [1-9] set, it will take all numbers from 1 to 9. Note that there is an alternation (??) used, after which another set of [1-9]. The check for 2nd digit includes ?d?. Alternation includes both the options.
Ø This is an expression for checking whole numbers between 1 to 100. So, finally include 100 also in the alternation.
Happy Programming...
Saturday, May 14, 2005
Microsoft Tech-Ed 2005
Microsoft Tech-Ed 2005 is coming up at chennai on June 20th. Find more details below:
http://www.microsoft.com/india/connections/teched2005/
Enjoy....
Difference between null and DBNull.Value
System.DBNull class differentiates between a null value and uninitialized value. In database application, a null object is a valid value for a field.
And moreover, if we put a null value in SqlParameter, it is as though the parameter did not exist (so it had better be optional), but if you put in DBNull.Value, the parameter is included with a null value
DBNull is never equal to anything. Of DBNull class only one instance can exist as it a singleton class. Sole instance is DBNull.Value.
Monday, May 09, 2005
Confirmation when deleting a record in the datagrid.
There are 2 possible ways to handle this scenario..
First solution is that, there are checkboxes in each row and on selecting the row, and click the delete button the records are deleted.
In Page load of the code-behind file,
btnDelete.Attributes.Add ("onClick", "return validate ('delete') ;"); // btndelete is command button
Add a client side method in UI,
function validate (Action)
{
if (! checkbox selected)
alert (?select any checkbox?); return false;
else
{
if (confirm("Are you sure you want to " + Action + " the selected User(s)?"))
return true;
else
return false;
}
}
And second solution is that, there are buttons in each row and on click the delete button the records are deleted.
In Page load of the code-behind file,
Call the Method, AddAttribute();
private void AddAttribute()
{
foreach( DataGridItem di in Datagrid1.Items)
{
LinkButton lnkBtn = (LinkButton)di.FindControl("lnkBtnDelete") ;
cmdBtn.Attributes.Add("onClick", "return confirm('Are you sure, you wish to delete this record?');");
}
}
In UI part,
<asp:TemplateColumn HeaderText="Delete">
<ItemTemplate>
<asp:LinkButton ID="lnkBtnDelete" Runat="server" CausesValidation="false" CommandName="Delete">Delete</asp:LinkButton>
</ItemTemplate>
</asp:TemplateColumn>
Happy Programming,
Kannan
Monday, April 18, 2005
Maintaining Checkbox state in Datagrid with paging
Whenever on click of the checkbox, we call a javascript function passing ‘this’ as parameter, so that we know which checkbox we are checking. Anyway, for each checkbox, we must be having a unique PK or some value.
The logic is like this,
If checkbox is checked, then append it to hidden variable with CSV (comma separated values), else if u uncheck it, split it and loop thru the remaining values and append the remaining checked values with CSV to hidden variable. The hidden field as below,
[input type="hidden" id="hdnField" name=" hdnField” value="[%=Request.Form("hdnField")%]"]
Note: (Replace "[]" with "<>")
The script can be downloaded from: Script.txt
Hope this works…..Happy programming
