can I use a dynamic entity context in my method?

asp.net c# dynamic-linq entity-framework-5 generics

Question

I have a method for gridview sorting and paging which I am trying to make reusable for generic types but I am struggling to figure out how to make the entity context (MyContext) and table (tblReports) dynamic variables - can anyone help me out please?

protected void PopulateGridView<T>(GridView grid)
{
    string columnToSortBy = (string)(ViewState["gridview_sortbycolumn"] ?? string.Empty);
    SortDirection sortDirection = (SortDirection)(ViewState["gridview_sortdirection"] ?? SortDirection.Descending);
    int pageIndex = (int)(ViewState["gridview_pageindex"] ?? 0);
    int pageSize = grid.PageCount;

    using (MyContext db = new MyContext())
    {
        if (columnToSortBy != string.Empty)
        {
            var query = db.tblReports.OrderBy(columnToSortBy + " " + sortDirection).Skip(pageIndex * pageSize);
            grid.DataSource = query.ToList();
        }
        else
        {
            string defaultColumn = string.Empty;

            foreach (var field in typeof(T).GetFields(BindingFlags.NonPublic | BindingFlags.Public | BindingFlags.Instance))
            {
                defaultColumn = field.Name.Remove(field.Name.IndexOf(">")).Replace("<", string.Empty);
                break;
            }

            var query = db.tblReports.OrderBy(defaultColumn).Skip(pageIndex * pageSize);
            grid.DataSource = query.ToList();
        }

        grid.PageIndex = pageIndex;
        grid.DataBind();
    }
}
1
1
9/5/2013 10:35:34 AM

Accepted Answer

Managed to get it working by passing the entity table as a parameter as suggested by @Jeroen and casting the linq query result to generic type.

Here is the final code for anyone who is interested :

protected void PopulateGridView<T>(GridView grid, DbSet entityTable)
{
    string columnToSortBy = (string)(ViewState["gridview_sortbycolumn"] ?? string.Empty);
    SortDirection sortDirection = (SortDirection)(ViewState["gridview_sortdirection"] ?? SortDirection.Descending);
    int pageIndex = (int)(ViewState["gridview_pageindex"] ?? 0);

    if (columnToSortBy != string.Empty)
    {
        grid.DataSource = entityTable.OrderBy(columnToSortBy + " " + sortDirection).Cast<T>().ToList();
    }
    else
    {
        // use linq reflection to get the first entity field name to sort by
        string defaultColumn = string.Empty;

        foreach (var field in typeof(T).GetFields(BindingFlags.NonPublic | BindingFlags.Public | BindingFlags.Instance))
        {
            defaultColumn = field.Name.Remove(field.Name.IndexOf(">")).Replace("<", string.Empty);
            break;
        }

        grid.DataSource = entityTable.OrderBy(defaultColumn).Cast<T>().ToList();
    }

    grid.PageIndex = pageIndex;
    grid.DataBind();
}
0
9/5/2013 1:05:36 PM


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