Techie's Diary

While working with file upload control, it is common requirement that user should upload only flie type that suits requirement. For example there is option of uploading resume in your application, resume is normally word or Pdf document, now suppose there is no validation of required file types and user uploaded image file or excel file instead of document, so here come loophole in your application. We can validate required file type either using JavaScript or we can use RegularExpression Validator to validate file. Here I am writing example for RegularExpressionValidator:  < asp : FileUpload ID ="fileUpload" runat ="server" /> < asp : RegularExpressionValidator ID ="regFileType" runat ="server" ControlToValidate =" fileUpload" Text ="*Only accepted file formats are pdf, doc and docx"   ValidationExpression ="^.+(.pdf|.PDF|.doc|.DOC|.docx|.DOCX)$" ValidationGroup ="vg"

In my last post I have described how you can get a comma separated string of selected value of a CheckBoxList or Listbox. In this example I am writing a method which will take string of values (comma separated) and CheckBoxList/ListBox as parameter and populate provided control. In few examples I have found that user have iterated over two loops to populate selected items, but here I am iterating over only Control’s item and then make use of LINQ over splitted string instead of iterating over it. So here comes power of LINQ over normal iterating code and this is more efficient way of doing this as we needn’t to run loop inside another loop and just one line of LINQ code served our purpose. Note: Please include   System.Text  and   System.Web.UI.WebControls  and System.Linq namespaces for this sample code. So here we go: //for Listbox:pass ListBox control. private void PopulateSelectedItems( string selectedItems, CheckBoxList control) {     if (! s

If you want to store selected value of a CheckBoxList or Listbox in comma separated string, then you are on right place. Sometime it is requirement that we want a comma separated string of selected value of CheckBoxList or Listbox control (I.e. to save your Control’s selected value in one String field of DB). So here I am writing one small function which will take CheckBoxList or ListBox as parameter and return comma separated string of selected items. Note: Please include System.Text and System.Web.UI.WebControls namespaces for this sample code. //for Listbox:provide ListBox control. public string GetSelectedItems( CheckBoxList control) {     var items = new StringBuilder ();     foreach ( ListItem item in control.Items)     {         if (item.Selected)             items.Append( string .Format( "{0}," , item.Value));     }     //Remove last comma before returning back.     return items.ToString().TrimEnd( '

So here I am writing another extension method for String to validate if sting value is a valid Guid or not with the help of regular expression. using System; using System.Text.RegularExpressions; public static class StringExtensions {     public static bool IsValidGuid( this String inputValue)     {         Regex isGuid = new Regex ( @"^(\{){0,1}[0-9a-fA-F]{8}\-[0-9a-fA-F]{4}\-[0-9a-fA-F]{4}\-[0-9a-fA-F]{4}\-[0-9a-fA-F]{12}(\}){0,1}$" , RegexOptions .Compiled);         bool isValid = false ;         if (! String .IsNullOrWhiteSpace(inputValue))         {             isValid = isGuid.IsMatch(inputValue);         }         return isValid;     } } And here is how you can use this: String testString = "6FE4851B-27A9-4D18-A51D-36B262023F39" ; if (testString.IsValidGuid()) {     Response.Write( "String is a valid GUID" ); } else {     Response.Write( &quo

There are sometime requirement that user should get a confirmation before performing an action, i.e. for example when click on Delete link,   you want a confirmation from user whether he/she is really want to delete or they accidently clicked on delete link. So here I'm showing how you can show confirmation box. < script type ="text/javascript">     function confirmDelete(delUrl) {         if (confirm( "Are you sure you want to delete this record?" )) {             return true ;         }         return false ;     } </ script > And call this function as: < a href ="javascript:return confirmDelete();"> Delete </ a > Another way We can write JavaScript confirm code inline as well: < a onclick ="javascript:return confirm('Are you sure you want to delete this record?');"> Delete </ a >

While working some time we need to encode or decode our string that contains HTML. Here is the example of encoding and decoding the html string: using System; using System.Web; using System.Diagnostics; using System.Web.UI; public partial class Default : Page {         protected void Page_Load( object sender, EventArgs e)         {             String originalValue = "<h1>This is Test Header</h1>" ;             String encodedValue = HttpUtility .HtmlEncode(originalValue);             String decodedValue = HttpUtility .HtmlDecode(encodedValue);             Debug .WriteLine(originalValue);             Debug .WriteLine(encodedValue);             Debug .WriteLine(decodedValue);         } } The output will be: <h1>This is Test Header</h1> &lt;h1&gt;This is Test Header&lt;/h1&gt; <h1>This is Test Header</h1> If you are using

One of my friends wanted to learn entity framework and requested me for a running sample of entity framework file. Here I am writing an entity framework sample application to demonstrate the whole idea of entity and we can check how powerful it is while we walk through the sample. Before starting with application part, I have already one DB “ Test_DB ” which I will use in this sample application. You can check I have three tables in the DB to check the relationship between tables let’s see the DB diagram for this DB. Here you can check “ tb_Section ” and “ tb_Class ” are referenced in table “ tb_Student ”. ( One thing you should make sure that table should be properly referenced if you wanted to make full and powerful use of Entity Framework ). So our DB is ready now let’s starting with our application. Open Visual Studio and add Blank Solution and name it as “ TestApplication ”. After that add new ASP.Net Application project to this solution and nam

In this article, we’ll see the different ways to hold constant or static values in C#. const: In C#, you can declare a const of any type as long as the value assigned can be fully evaluated at compile time. A constant member is defined at compile time and cannot be changed at runtime. Constants are declared as a field using the const keyword, and must be initialized along with its declaration as shown below: public class TestClass { public const double DaysInWeek = 7; public const string FullNameFormat = "Mr." + "{0} {1}"; public const string FullNameFormatEmpty = string.Empty; //Invalid because of string.Empty evaluated on runtime } Constants are Static by default, Constants are accessed as if they were static fields, and we can’t use  static  keywords with  const . The constant cannot be changed in the application anywhere else in the code as this will cause a compiler error. Constants must be a value type ( byte ,  short ,  ushort ,  int ,  uint ,  long ,