Codelab Blog » .NET Framework

Perform ASP.NET Postback using JQuery

Tim — Wed, 26 Oct 2011 23:47:24 +0000

Came across a situation where I needed to disable the ASP.NET button using JQuery when the user clicks on the button, this is so we stop the user from clicking the button twice while the page is doing a postback.

Firstly, add the following JQuery/Javascript code:

You can inject the correct generated javascript code from using the function GetPostBackEventReference between the server tags. Bind a click event to the ASP.NET server control which disables the button and call the autosubmit javascript function to perform a post back on the ASP.NET button control.

References

http://msdn.microsoft.com/en-us/library/ms153112.aspx

Some useful Extension Methods

Tim — Tue, 06 Sep 2011 10:45:59 +0000

Back to basics…

A couple of useful Extension methods if you are checking if a string is a valid integer or decimal.

public static bool IsInteger(this string value)
{
if (String.IsNullOrEmpty(value)) return false;
Int32 tmpNo;
return Int32.TryParse(value, out tmpNo);
}

public static bool IsDecimal(this string value)
{
if (String.IsNullOrEmpty(value)) return false;
Decimal tmpNo;
return Decimal.TryParse(value, out tmpNo);
}

To implement the Extension Methods:

var myString = "10.5";

if (myString.IsDecimal())

{

//Do something

}

Finding StoreGeneratedPattern value in EdmProperty in T4 Template

Tim — Wed, 11 May 2011 03:11:05 +0000

If you need to find out if a primary key in your conceptual model which is using the Identity value from the property StoreGeneratedPattern, you can use the following code: (NOTE: This is used within a T4 template)

string inputFile = @"..\EntitiesModel.edmx";
EdmItemCollection ItemCollection = loader.CreateEdmItemCollection(inputFile);
string annotationNamespace = "http://schemas.microsoft.com/ado/2009/02/edm/annotation";

foreach (EntityType entity in ItemCollection.GetItems().OrderBy(e => e.Name)) {
foreach (EdmProperty edmProperty in entity.Properties.Where(p => p.TypeUsage.EdmType is PrimitiveType && p.DeclaringType == entity)) {

MetadataProperty storeGeneratedPatternProperty = null;
edmProperty.MetadataProperties.TryGetValue(annotationNamespace + ":StoreGeneratedPattern", false, out storeGeneratedPatternProperty);

if (storeGeneratedPatternProperty != null && storeGeneratedPatternProperty.Value.ToString() == "Identity") {
//We found an Identity property
}
}
}

You receive a “The incoming tabular data stream (TDS) remote procedure call (RPC) protocol stream is incorrect” exception when using NVarchar parameters with Sqlclient

Tim — Thu, 26 Aug 2010 00:02:33 +0000

The problem

I got the following random error:

You receive a “The incoming tabular data stream (TDS) remote procedure call (RPC) protocol stream is incorrect” exception when using NVarchar parameters with Sqlclient

The Solution

Its a known bug with the .Net SqlClient Data Provider. If you have a field in the database of type nvarchar(max) or greater than 4000 characters and if the user enters data into the field greater than 4000 characters via the .Net SqlClient Data Provider you will receive an exception.

To get around this, reduce the field size to less that 4000 characters or change your type to ntext or set the Sqlparamter.size property to -1 to allow the entire data to be saved.

References

http://support.microsoft.com/kb/970519

Open XML – OLE Automation Date Issues

Tim — Sun, 25 Jul 2010 12:16:20 +0000

If you are exporting a date from C# to Excel using 2007, you probably will use the following:

Math.Round(DateTime.Now.ToOADate(), 12).ToString()

This exports the date as a OLE Automation date recognized by Excel 2007. How ever, in Excel 2010 this was causing issues, every time I exported to Excel 2010, it said that it has to repair my document and it never displayed the values correctly as dates.

Because I was using Open XML to generate the markup, Excel 2010 has been support for Open XML. I got around the problem of using:

DateTime.Now.ToString("yyyy-MM-dd'T'HH:mm:ss.fffffffzzz");

This exports the date as a XML Date format.
Hope this helps anyone who has the same problem!

EF Strongly Typed ObjectQuery.Include

Tim — Mon, 12 Jul 2010 20:37:58 +0000

The problem that I faced was having to put up with “hard coded” strings in the ObjectQuery.Include function to load related objects through POCO objects in the Entity Framework. This faced challenges when I renamed columns in the Model which caused a run-time error when recompiling and re-starting the application. Thanks to David Kiff, we can now change the code from being strings:

using (CommuicationsEntities entities = new CommuicationsEntities())
{
entities.Order.Include("OrderDetails");
}

To a nice strongly typed includes using a IncludeBuilder class.

public class IncludeBuilder
{
private readonly List _propertiesToInclude;

public IncludeBuilder()
{
_propertiesToInclude = new List();
}

public void Add(Expression> propertySelector)
{
MemberExpression memberExpression = propertySelector.Body as MemberExpression;
if (memberExpression == null)
throw new ArgumentException("Parameter propertySelector must be a MemberExpression");
_propertiesToInclude.Add(memberExpression.Member.Name);
}

public ObjectQuery Includes(ObjectQuery query)
{
foreach (string include in _propertiesToInclude)
{
query = query.Include(include);
}
return query;
}
}

the following code calls the include builder, includes the relationship and gets a simple list with no tracking on the POCO objects.

IncludeBuilder _include = new IncludeBuilder();
_include.Add(a => a.Orders);
ObjectQuery customers= DataContext.Servers;
return _include.Includes(customers).Execute(MergeOption.NoTracking).ToList();

References:

http://davidkiff.co.uk/post/2009/08/27/EF-Strongly-Typed-ObjectQuery3cT3eInclude%28e2809ce2809d%293b.aspx

Fixing the EF Tracing and Caching Provider Wrapper Issue

Tim — Fri, 09 Jul 2010 04:20:59 +0000

If you have been using the Tracing and Caching Provider Wrappers for the ADO.NET Entity Framework 4.0, you might of come across this error message when creating POCO objects, adding them to a Data Context and commiting them to the database using the Caching Wrapper:

[NotImplementedException: The method or operation is not implemented.]
   EFCachingProvider.EFCachingDataReaderCacheWriter.GetName(Int32 ordinal) in EFCachingProvider\EFCachingDataReaderCacheWriter.cs:109
   System.Data.Mapping.Update.Internal.DynamicUpdateCommand.Execute(UpdateTranslator translator, EntityConnection connection, Dictionary`2 identifierValues, List`1 generatedValues) +8118458
   System.Data.Mapping.Update.Internal.UpdateTranslator.Update(IEntityStateManager stateManager, IEntityAdapter adapter) +267

Line 107:        public override string GetName(int ordinal)
Line 108:        {
Line 109:            throw new NotImplementedException();
Line 110:        }
Line 111:

Basically, the author’s of the code have created a wrapper for the DBDataReader class and have not implement the override methods. This can be fixed by calling the Wrapper DataReader object methods. This is what I have modified in the EFCachignDataReaderCacheWriter.cs file:

using System;
using System.Data;
using System.Data.Common;
using EFCachingProvider.Caching;

namespace EFCachingProvider
{
///
/// Implementation of the which reads the results of another data reader
/// and stores a copy in the cache.
///
internal class EFCachingDataReaderCacheWriter : EFCachingDataReaderBase
{
private DbQueryResults queryResults = new DbQueryResults();
private DbDataReader wrappedReader;
private int maxRows;
private Action addToCache;

///
/// Initializes a new instance of the EFCachingDataReaderCacheWriter class.
///
///
The wrapped reader. ///
The maximum number of rows which can be cached. ///
The delegate used to add the result to the cache when the reader finishes. public EFCachingDataReaderCacheWriter(DbDataReader wrappedReader, int maxRows, Action addToCache)
{
this.wrappedReader = wrappedReader;
this.addToCache = addToCache;
this.maxRows = maxRows;
}

///
/// Gets a value that indicates whether this contains one or more rows.
///
///
/// true if the contains one or more rows; otherwise false.
///
public override bool HasRows
{
get { return this.wrappedReader.HasRows; }
}

///
/// Gets the number of rows changed, inserted, or deleted by execution of the SQL statement.
///
///
///
/// The number of rows changed, inserted, or deleted. -1 for SELECT statements; 0 if no rows were affected or the statement failed.
///
public override int RecordsAffected
{
//get { throw new NotImplementedException(); }
get { return this.wrappedReader.RecordsAffected; }
}

///
/// Gets a value indicating whether the is closed.
///
///
/// true if the is closed; otherwise false.
///
public override bool IsClosed
{
//get { throw new NotImplementedException(); }
get { return this.wrappedReader.IsClosed; }
}

///
/// Gets a value indicating the depth of nesting for the current row.
///
///
///
/// The depth of nesting for the current row.
///
public override int Depth
{
//get { throw new NotImplementedException(); }
get { return this.wrappedReader.Depth; }
}

///
/// Gets name of the data type of the specified column.
///
///
The zero-based column ordinal. ///
/// A string representing the name of the data type.
///
public override string GetDataTypeName(int ordinal)
{
//throw new NotImplementedException();
return this.wrappedReader.GetDataTypeName(ordinal);
}

///
/// Gets the data type of the specified column.
///
///
The zero-based column ordinal. /// The data type of the specified column.
public override Type GetFieldType(int ordinal)
{
return this.wrappedReader.GetFieldType(ordinal);
}

///
/// Gets the name of the column, given the zero-based column ordinal.
///
///
The zero-based column ordinal. /// The name of the specified column.
public override string GetName(int ordinal)
{
return this.wrappedReader.GetName(ordinal);
}

///
/// Gets the column ordinal given the name of the column.
///
///
The name of the column. /// The zero-based column ordinal.
///
/// The name specified is not a valid column name.
///
public override int GetOrdinal(string name)
{
return this.wrappedReader.GetOrdinal(name);
}

///
/// Returns a that describes the column metadata of the .
///
///
/// A that describes the column metadata.
///
public override DataTable GetSchemaTable()
{
return this.wrappedReader.GetSchemaTable();
}

///
/// Advances the reader to the next result when reading the results of a batch of statements.
///
///
/// true if there are more result sets; otherwise false.
///
public override bool NextResult()
{
if (this.wrappedReader.NextResult())
{
this.queryResults = null;
return true;
}
else
{
return false;
}
}

///
/// Closes the object.
///
public override void Close()
{
this.wrappedReader.Close();

if (this.queryResults != null)
{
this.addToCache(this.queryResults);
}
}

///
/// Advances the reader to the next record in a result set.
///
///
/// true if there are more rows; otherwise false.
///
public override bool Read()
{
if (this.wrappedReader.Read())
{
object[] values = new object[this.wrappedReader.FieldCount];

this.wrappedReader.GetValues(values);
SetValues(values);
if (this.queryResults != null)
{
this.queryResults.Rows.Add(values);
if (this.queryResults.Rows.Count > this.maxRows)
{
this.queryResults = null;
}
}

return true;
}
else
{
return false;
}
}
}
}

Random number of items from a Generic List extension method

Tim — Sun, 13 Jun 2010 09:58:36 +0000

Here is a code snippet for returning N number of items from a generic list using a extension method. This requires .NET 3.5.

public static class Extensions
{
///

/// method for returning N number of random items from a generic list
///

/// Item type
/// Generic list we wish to retrieve from
/// number of items to return
///
public static IEnumerable Randomize(this List list, int count)
{
List randomList = new List();
Random random = new Random();

while (list.Count > 0)
{
//get the next random number between 0 and
//the list count
int idx = random.Next(0, list.Count);

//get that index
randomList.Add(list[idx]);

//remove that item so it cant be added again
list.RemoveAt(idx);
}

//return the specified number of items
return randomList.Take(count);
}

///

/// method for returning 1 item from the generic list
///

/// Item type
/// Generic list we wish to retrieve from
/// number of items to return
///
public static T Randomize(this List list)
{
return Randomize(list, 1).FirstOrDefault();
}
}

used in code by calling the following: List = myGenericList.Randomise(5) or mytype = myGenericList.Randomise();

Could not load file or assembly ‘NameOfAssemblyGoesHere’

Tim — Fri, 11 Jun 2010 04:46:00 +0000

Encounted the following error:

Could not load file or assembly ‘NameOfAssemblyGoesHere’ or one of its dependencies. An attempt was made to load a program with an incorrect format.

The problem happened when deploying a web application to a 64bit server where all the required DLL’s where marked as running only on a 32bit system. You can change this by setting the target platform to AnyCPU which will solve this issue. There is another workaround which is setting IIS compatability mode to 32bit, Open a command prompt and navigate to the %systemdrive%\Inetpub\AdminScripts directory. Type in the command cscript.exe adsutil.vbs set W3SVC/AppPools/Enable32BitAppOnWin64 “true”.

Change username in ASP.NET Membership Provider

Tim — Sun, 30 May 2010 22:11:33 +0000

Found a great article here about the process of changing the username with the ASP.NET Membership Provider.

Here is a summary of the process that I found best useful which is one of the comments:

1. Make sure New UserName is Unique

2. Update the aspnet_Users table directly

3. Execute to following code to change the username/cookie/identity without leaving the webpage…

‘ Obtains the name of the FormsAuthentication Cookie, uses that name to request the Cookie and Decrypts the Cookies information into a AuthTicket

Dim AuthTicket As FormsAuthenticationTicket = FormsAuthentication.Decrypt(HttpContext.Current.Request.Cookies(FormsAuthentication.FormsCookieName).Value)

‘ Instantiates a new user identity authenticated using forms authentication based on the FormsAuthenticationTicket.

‘ The FormsAuthenticationTicket has been created using the exact same parameters of the user with the Old Username except the Old Username has been updated with the New Username.

Dim NewFormsIdentity As New FormsIdentity(New FormsAuthenticationTicket(AuthTicket.Version, NewUsername, AuthTicket.IssueDate, AuthTicket.Expiration, AuthTicket.IsPersistent, AuthTicket.UserData))

‘ Parse out the AuthTicket’s UserData into a string array of Roles

Dim Roles As String() = AuthTicket.UserData.Split(“|”.ToCharArray)

‘ Creates a new user that has the NewFormsIdentity and belongs to the array of Roles, if any, that was stored in the FormsAuthenticationTicket

Dim NewGenericPrincipal As New System.Security.Principal.GenericPrincipal(NewFormsIdentity, Roles)

‘ Sets the security information for the current HTTP request to the new user. The Username has now been changed (i.e. HttpContext.Current.User.Identity.Name = NewUsername, prior to this step is was the OldUsername)

HttpContext.Current.User = NewGenericPrincipal

‘ Removes the forms-authentication ticket from the browser

FormsAuthentication.SignOut()

‘ Cancels the current session

HttpContext.Current.Session.Abandon()

‘ Creates an authentication ticket for the supplied New Username and adds it to the cookies collection of the response or the URL

FormsAuthentication.SetAuthCookie(HttpContext.Current.User.Identity.Name, AuthTicket.IsPersistent)

4. Response.Redirect back to the same page if needed.

References:

http://omaralzabir.com/how_to_change_user_name_in_asp_net_2_0_membership_provider/