how to Get by Id data from database Blazor C#

Question

already have started crud with blazor serverside to get data from database

i am working now to create a page where i will see details and edit one item of a list

i got the id of the item i want to display but my crud solution give me a list of object not just one llike i need....

i got my SqlDataAccess where i code the two main function (load -> QueryAsync, and Save -> ExecuteAsync) with its interface like below :

And i got a FiledbData class from where i call db like below :

i want now just to ask the database for one item like an getbyId instead of get all data ...

Answer 1

You can use parameterized queries to execute an where clause.

Therefore the GetFile method would be like this:

public Task<FileModel> GetFilebyId(int id)
{
    string sql = "select * from dbo.file.. where Id = @Id";
    return _db.LoadSingleResult<FileModel, dynamic>(sql, new  {Id = id });
}

Also you need to add a new method LoadSingleResult like below(other parts apart from try section are similar to your LoadData method):

public async Task<T> LoadSingleResult<T,U>(string sql, U parameters)
{
   .
   .
   .
   try{
       var data=await connection.QueryAsynch<T>(sql, parameters);
       reurn data.Single();
   }
   .
   .
   .
}

Note that:

• The id column assumed to be Id.
• The id column assumed to be an integer column

You can use QuerySingleOrDefaultAsync too.