There is already an open DataReader associated with this Command which must be closed first
When your MVC 5 web application page tries to read the database using the Entity Framework in a loop you may get the following error message: InnerException: System.InvalidOperationException HResult=-2146233079 Message=There is already an open DataReader…
Windows web service authentication in IIS Express
When you develop a SOAP web service in Visual Studio 2013 the IDE uses IIS Express for testing. To set up Windows authentication in IIS Express follow the steps below: Create a Local Security Group on your computer Right click Computer and select Manage…
How to add tooltip to a Windows Form
In Windows Form applications the tooltip functionality is not built into the controls as in HTML objects. To add tooltip to your controls on Windows Forms Open the Windows Form in the designer Drag the ToolTip control from the Common Controls section of…
How to add a DataGridView to a Windows Form
To display data in a DataGridView on a Windows Form Add a new form to the Win Form Application project Drag a BindingSource from the Toolbox to the form The bindingSource object appears below the form Rename the Binding Source Select the…
DbArithmeticExpression arguments must have a numeric common type
The Microsoft Visual Studio 2013 Entity Framework database query does not support the subtraction of two dates to calculate TimeSpan. For example the following statement will throw a runtime error: site.VisitFrequencySec < ((TimeSpan)(dtNow -…
The underlying provider failed on Open
When you get the following error message in Microsoft Visual Studio 2013 check the inner exception. System.Data.Entity.Core.EntityException was unhandled HResult=-2146233087 Message=The underlying provider failed on Open. Source=EntityFramework The…
The Entity Framework provider … could not be loaded
When you create a new Microsoft Visual Studio 2013 project that uses the Entity Framework you may get the following error message: The Entity Framework provider type ‘System.Data.Entity.SqlServer.SqlProviderServices,…
Microsoft Azure – Storage – Part 5 – Delete blobs with a .NET application
In the prior article of the Microsoft Azure storage series we have downloaded a file (blob) from the container. In this part we will add a method to delete a blob in the Azure storage container. Delete a blob in the storage container Add the DeleteBlob…
Microsoft Azure – Storage – Part 4 – Download files with a .NET application
In the third part of the Microsoft Azure Storage series we have extended our .NET application to list the contents of a container. Today we will add a method to our application to download files from the storage container. Download blobs from the…
Microsoft Azure – Storage – Part 3 – List the contents of the container with a .NET application
In the second part of the Azure Storage series we have developed a .Net application that can create a Microsoft Azure storage container and upload files into it. Today we will extend the functionality of our application to list the files in the…