To communicate from .NET code to MySQL database using Entity Framework we installed MySql .NET Connector. It worked fine out of the box on developer's workstations but once deployed to hosted web server application started to throw following error:
[NotSupportedException: Unable to determine the provider name for connection of type 'MySql.Data.MySqlClient.MySqlConnection'.] System.Data.Entity.ModelConfiguration.Utilities.DbConnectionExtensions.GetProviderInvariantName(DbConnection connection)
System.Data.Entity.ModelConfiguration.Utilities.DbConnectionExtensions.GetProviderInfo(DbConnection connection, DbProviderManifest& providerManifest)
System.Data.Entity.DbModelBuilder.Build(DbConnection providerConnection)
System.Data.Entity.Internal.LazyInternalContext.CreateModel(LazyInternalContext internalContext)
System.Data.Entity.Internal.RetryLazy`2.GetValue(TInput input)
System.Data.Entity.Internal.LazyInternalContext.InitializeContext()
System.Data.Entity.Internal.InternalContext.GetEntitySetAndBaseTypeForType(Type entityType)
System.Data.Entity.Internal.Linq.InternalSet`1.Initialize()
System.Data.Entity.Internal.Linq.InternalSet`1.get_InternalContext()
System.Data.Entity.Internal.Linq.InternalSet`1.ActOnSet(Action action, EntityState newState, Object entity, String methodName)
System.Data.Entity.Internal.Linq.InternalSet`1.Add(Object entity)
System.Data.Entity.DbSet`1.Add(TEntity entity)
Apparently, somehow MySQL .NET provider was not registered on server although installation was done properly and all assemblies were present in GAC. Since on shared hosting we did not have access to machine.config by adding the same registration entry to the application web.config file resolved the issue:
<system.data>
<DbProviderFactories>
<add name="MySQL Data Provider" invariant="MySql.Data.MySqlClient" description=".Net Framework Data Provider for MySQL" type="MySql.Data.MySqlClient.MySqlClientFactory, MySql.Data, Version=6.4.3.0, Culture=neutral, PublicKeyToken=c5687fc88969c44d"/>
</DbProviderFactories>
</system.data>
Important: 1) Make sure to register the same version that is installed on the server 2) Provide precise fully qualified name in the type attribute. For example, adding extra space between MySql.Data.MySqlClient.MySqlClientFactory and MySql.Data will make this entry useless and will result in the same error
There are several conditions that are applied to partial methods, such as:
Partial methods must be void
Signatures of both parts of partial methods must match
Access modifiers are not allowed for partial methods
Partial methods must be declared in partial classes
etc
You don’t have to remember all these conditions if you have the CodeRush code issues feature turned on. When the rule of the partial method declaration is violated, code issues will show you an error or a hint, and you can fix it before you compile the code. These code issues are:
Partial method cannot have access modifiers or the virtual, abstract, override, new, sealed, or extern modifiers
If a partial method has an invalid modifier (e.g., virtual, abstract, override, new, sealed, extern, or an access modifier) you will see an error in the code editor, because partial methods cannot have these type of modifiers:
CodeRush Partial method cannot have modifiers
CodeRush Partial method cannot have access modifiers
Partial method cannot have out parameters
Out parameters are not allowed for partial methods. If a partial method is declared with ‘out’ parameters, you will see an error:
CodeRush Partial method cannot have out parameters
Partial method must be declared within a partial class or partial struct
Partial methods can only reside inside a partial class or a partial structure, otherwise, an error is shown:
CodeRush Partial method must be declared within a partial class
Partial method has only single part
When the partial method has only a single part without a declaration, it does not need to be declared as partial. This code issue has a hint type:
CodeRush Partial method has only single part
To enable filtering, we’ll update our GetProducts() method to take a keyword parameter like below:
public IQueryable<Product> GetProducts([QueryString]string keyword)
{
IQueryable<Product> query = db.Products;
if (!String.IsNullOrWhiteSpace(keyword))
{
query = query.Where(p => p.ProductName.Contains(keyword));
}
return query;
}
If the keyword is empty or null, then the method returns all of the products in the database. If a keyword is specified then we further filter the query results to only include those product’s whose names contain the keyword.
Understanding Value Providers
One of the things you might have noticed with the code above is the [QueryString] attribute that we’ve applied to the keyword method argument. This instructs the Model Binding system to attempt to “bind” a value from the query string to this parameter at runtime, including doing any type conversion required.
These sources of user values are called “Value Providers”, and the parameter attributes used to instruct the Model Binding system which Value Provider to use are called “Value Provider Attributes”. The next version of Web Forms will ship with value providers and corresponding attributes for all the common sources of user input in a Web Forms application, e.g. query string, cookies, form values, controls, viewstate, session and profile. You can also write your own custom value providers. The value providers you write can be authored to work in both Web Forms and MVC.
By default, the parameter name will be used as the key in the value provider collection, so in this case, a value will be looked for in the query string with the key “keyword”, e.g. ~/Products.aspx?keyword=chef. This can be easily overridden by passing the desired key in as an argument to the parameter attribute. In our example, we might like the user to be able to use the common “q” query string key for specifying the keyword:
public IQueryable<Product> GetProducts([QueryString("q")]string keyword)
Entry Level
Property Change NOtification (INotifyPropertyChange and ObservableCollection)
ResourceDictionary
UserControls
Mid Level
Blend/Cider
animations and storyboarding
ClickOnce Deployment
Senior
WPF 3D
Differences between Silverlight 2 and WPF
MVVM/MVP
WPF Performance tuning
Pixel Shaders
Entry Level
Mid Level
Senior
DirectX is definitely not dead and is still more appropriate than WPF for advanced developers writing hard-core “twitch games” or applications with complex 3D models where you need maximum performance. That said, it’s easy to write a naive DirectX application that performs far worse than a similar WPF application. DirectX is a low-level interface to the graphics hardware that exposes all of the quirks of whatever GPU a particular computer has. DirectX can be thought of as assembly language in the world of graphics: You can do anything the GPU supports. WPF provides a high-level abstraction that takes a description of your scene and figures out the best way to render it, given the hardware resources available. Internally, this might involve using Shader Model 3.0, or the fixed-function pipeline, or software. (Don’t worry if you’re not familiar with these terms, but take it as a sign that you should be using WPF!). The downside of choosing DirectX over WPF is a potentially astronomical increase in development cost. A large part of this cost is the requirement to test your application on each driver/GPU combination you intend to support. One of the major benefits of building on top of WPF is that Microsoft has already done this testing for you! You can instead focus your testing on low-end hardware for measuring performance. The fact that WPF applications can even leverage the client GPU over Remote Desktop or in a partial-trust environment is also a compelling differentiator.
WPF is Object Oriented , XAML based.
It is used for the
Routed Events & Commands
Converters - Added by Artur Carvalho
Explain WPF's 2-pass layout engine?
How to implement a panel?
Interoperability (WPF/WinForms)
Blend/Cider - Added by a7an
Animations and Storyboarding
ClickOnce Deployment
Skinning/Themeing
Custom Controls
How can worker threads update the UI?
DataTemplate vs HierarchicalDataTemplate
ItemsControl vs ItemsPresenter vs ContentControl vs ContentPresenter
Different types of Triggers
