What we're after is to create a link that looks like the following when the page runs, with the id value different for each movie:.
This link will invoke a page named EditMovie , and it will pass the query string? The syntax for the new column might look a bit complex, but that's only because it puts together several elements. Each individual element is straightforward. Some background about how the grid works: the grid displays rows, one for each database record, and it displays columns for each field in the database record.
While each grid row is being constructed, the item object contains the database record item for that row. This arrangement gives you a way in code to get at the data for that row. That's what you see here: the expression item. ID is getting the ID value of the current database item. You could get any of the database values title, genre, or year the same way by using item. Title , item. Genre , or item. NET operator that represents the current website root.
The result is that this part of the markup in the column simply produces something like the following markup at run time:.
Now back to the grid column. The three columns you originally had in the grid displayed only data values title, genre, and year. You specified this display by passing the name of the database column — for example, grid. Column "Title". This new Edit link column is different. Instead of specifying a column name, you're passing a format parameter. This parameter lets you define markup that the WebGrid helper will render along with the item value to display the column data as bold or green or in whatever format that you want.
For example, if you wanted the title to appear bold, you could create a column like this example:. The various characters you see in the format property mark the transition between markup and a code value.
Once you know about the format property, it's easier to understand how the new Edit link column is put together:. The column consists only of the markup that renders the link, plus some information the ID that's extracted from the database record for the row. Many times when you've called a method and passed parameters to it, you've simply listed the parameter values separated by commas.
Here are a couple of examples:. We didn't mention the issue when you first saw this code, but in each case, you're passing parameters to the methods in a specific order — namely, the order in which the parameters are defined in that method. For db. Execute and Validation. RequireFields , if you mixed up the order of the values you pass, you'd get an error message when the page runs, or at least some strange results.
Clearly, you have to know the order to pass the parameters in. In WebMatrix, IntelliSense can help you learn figure out the name, type, and order of the parameters. As an alternative to passing values in order, you can use named parameters. Passing parameters in order is known as using positional parameters.
For named parameters, you explicitly include the name of the parameter when passing its value. You've used named parameters already a number of times in these tutorials. For example:. Named parameters are handy for a couple of situations, especially when a method takes many parameters. One is when you want to pass only one or two parameters, but the values you want to pass are not among the first positions in the parameter list.
Another situation is when you want to make your code more readable by passing the parameters in the order that makes the most sense to you. Obviously, to use named parameters, you have to know the names of the parameters. WebMatrix IntelliSense can show you the names, but it cannot currently fill them in for you.
Now you can create the EditMovie page. When users click the Edit link, they'll end up on this page. Create a page named EditMovie. This markup and code is similar to what you have in the AddMovie page. There's a small difference in the text for the submit button. As with the AddMovie page, there's an Html. ValidationSummary call that will display validation errors if there are any. This time we're leaving out calls to Validation. Message , since errors will be displayed in the validation summary.
As noted in the previous tutorial, you can use the validation summary and the individual error messages in various combinations. As with the AddMovie. But when i click on delete i am taken to another page, where it will display the records that i chosed to delete and will ask if i want to delete the said record.
In this page the record i want to delete is not shown therefore i get an error. Any idea how i could solve this? I have updated my code above. SaveChanges ; To delete, use the opposite of. Add f ,. Paul Fleming Paul Fleming SaveChanges ;? I didn't test this code, it's freehand.
Error 1 A local variable named 'f' cannot be declared in this scope because it would give a different meaning to 'f', which is already used in a 'parent or current' scope to denote something else This is what i get.
Ah, yes, change it to something else. Say e for "entity" or f1. Because when i try to edit the 2nd or 3rd record it always goes and updates the 1st record in the DB. Show 4 more comments. Update: if ModelState. Friend where c.
Id select c. FirstOrDefault ; upd. ChangeObjectState f, EntityState. Modified ; myEntities. FirstOrDefault ; myEntities. DeleteObject del ; myEntities. Am i suppose to add some reference here? Introduction to ASP. Update Records using ADO. This tutorial is a part of ADO.
NET series. Learn ADO. NET Core Application 2. Create Records using ADO. NET Core Application 3. Read Records using ADO. NET Core Application 4. NET Core Application 5. Usin asp. Because to run that page you have to call that page from browser. Instead of that you can create Window Service that call automatically on certain time. And you can load that service to your like project IIS and that will call automatically in certain interval and perform database performance on that.
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