Entity framework when is connection opened

The only way to Auto-Fit a column is to scan through every row in the column and calculate the width of the text based on the characters and font used. You would use something like what I found here. Then take the max value of that and pad with 5. I would avoid this approach when processing spreadsheets in a web environment because you could be exporting hundreds of thousands of rows with tens of columns - you get the idea.

The best approach is to set a best-guess width for your columns and train your users on how to auto-fit from excel. Because I'm feeling generous, here's an example of how to get an approximate width for your column. I'd prefer to avoid doing this for all rows in a column, so let's just base our width by default on the value in your header cell. Below is how you could do this using the example I linked to earlier. Note: These are approximations, but close enough. Caveat : If you use this code in the same place you're using OpenXml, then you may need to remove the "using" for System.

Drawing and fully qualify "Font" and "FontStyle" as System. Font and System. Otherwise your compiler may mistake these classes as belonging to DocumentFormat. I just tested it and the problem was that Booking. DbContext won't keep connection open for re-use. Asked 4 Months ago Answers: 5 Viewed times. AreEqual ConnectionState. Closed, context. State ; context. Closed Assert. Open, context. Add newRecord ; context. Open context. NonPublic BindingFlags. GetProperty "Owner",BindingFlags.

Instance BindingFlags. I have noticed that at some point EF starts generating unions rather than joins but I am not sure what rules it applies and why.

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Post Comment. Want to advertise here and reach my savvy readers? SQL Server. When I measured the average query execution times, I got some unexpected results: CPU time: 12 milliseconds Reads: Elapsed time: milliseconds Wait, what?

I ran the query myself in Management Studio: CPU time: 17 milliseconds Reads: Elapsed time: milliseconds These numbers made a lot more sense, and confirmed that the application was to blame. Entity Framework will try to be clever about connections After some research, I found that Entity Framework can be sneaky about how it manages database connections.

An article about EF connection management on MSDN proved both enlightening and slightly terrifying: Entity Framework will handle database connections automatically by default. How to spot Entity Framework keeping connections open The tell-tale signs, as we discovered in this case are: When running the query from the application Relatively low CPU time but high elapsed time when running the query from the application.

Significant amounts of application code that execute in between the connection open event and close event. To prove the connection is left waiting during the open and close events, step through the code in a debugger and pause before the connection is closed. Remember, the events that open and close the connection may not be explicitly doing so. Leave new mark.

Both have them. Jonathan Allen. If instead he used Where …. Julie Lerman. Doug Lane. Jeff Emery. And as Julie states, monitoring queries delivered by your ORM is always advisable. Kendra Little. Just ask my opinion of Silverlight… Ha! Perhaps the best tactic is to make an educated decision and proceed deliberately….

Brent Ozar. Jaffar top. Richie Rump. I wish more devs were proactive like yourself! Ron Smith. Thanks for this post Doug. Example for Using EF6. For more information about the MySql. Edit the configuration sections in the app. NuGet package. Install the NuGet package to add this reference automatically to the app. For this option, select nuget. EntityFramework assembly to your project. Depending on the. NET Framework version used, the assembly is taken from the v4.

Always update the version number to match the one in the MySql. This step is optional but highly recommended, because it adds all the dependency resolvers for MySQL classes. This can be done in three ways:. Adding the DbConfigurationTypeAttribute on the context class:. Calling DbConfiguration. Set the DbConfiguration type in the configuration file:. It is also possible to create a custom DbConfiguration class and add the dependency resolvers needed. NET Standard 2.

Async Query and Save adds support for the task-based asynchronous patterns that have been available since. NET 4. To use this feature, add to the OnCreateModel method:.

Code-Based Configuration gives you the option of performing configuration in code, instead of performing it in a configuration file, as it has been done traditionally. Dependency Resolution introduces support for the Service Locator. Some pieces of functionality that can be replaced with custom implementations have been factored out. To add a dependency resolver, use:.

DbContext can now be created with a DbConnection that is already opened , which enables scenarios where it would be helpful if the connection could be open when creating the context such as sharing a connection between components when you cannot guarantee the state of the connection.

Improved Transaction Support provides support for a transaction external to the framework as well as improved ways of creating a transaction within the Entity Framework.