泛型C＃-将动态类型作为参数传递

Question

I ran into a small issue when trying to use SQL Queries with LinQ.

The object I am receiving is as below:

public class Entity {
   public int EntityId { get; set; }
   public string TableName { get; set; } 
}

Basically I need to run a script similar to this ..

var entityQuery = _context.Database.SqlQuery<T>("SELECT * FROM [dbo].[" + TableName + "] WHERE [Id]=" + EntityId).ToList();

Now the problem is that I can only know what type of object "T" is from the "TableName" property. How would I be able to instantiate the class in order to pass it instead of T?

Thanks :)

---

For those getting confused this is the method I am working on:

public void ModifyData(Entity item)
{
  var table = item.TableName;
  var id = item.EntityId;

  var entityQuery = _context.Database.SqlQuery<T>("SELECT * FROM [dbo].[" + table + "] WHERE [Id]=" + id ).ToList();

  //more code below;
}

Is there a different way to do this?

Answer 1

Why do you want to pass a tableName ? and too in a "int tableName" ? Why dont use the entity type passed in ? Well anyways, you can try something like this:

static string Data(string tableName, string columnNames, string orderBy)
{
  var type = Assembly.GetExecutingAssembly().GetTypes().FirstOrDefault(i => i.Name == tableName);
  using (var context = new BloggingEntities())
  {
    var data = Select(type, columnNames, orderBy, context);
    var str = JsonConvert.SerializeObject(data);
    return str;
  }
}

static string Select(Type type, string columnNames, string orderBy, BloggingEntities _dbContext)
{
  var data = _dbContext.Set(type).AsNoTracking().AsQueryable();
  var selectStatement = "new ( " + columnNames + ")";
  var filtered = data.Select(selectStatement).OrderBy(orderBy);
  return JsonConvert.SerializeObject(filtered);
}

Note: You may have to install this : Install-Package System.Linq.Dynamic

In your case you can directly use

var data = _dbContext.Set(type).AsNoTracking().AsQueryable();