Entity Framework 6 和带有标量变量的 DBContext 或 DBQuery 或 DBSet 或 ObjectQuery

Question

我正在尝试将一个变量传递给我的 DBContext 扩展。它适用于固定字符串，但当我尝试使用变量时出现错误“必须声明标量变量@p_linq_0”

        var pn = "6-10064-01";
        // put query results into datatable
        var query = db.SWD_0004.Where(p => p.Part_Number == pn) as DbQuery<SWD_0004>;
        var numResults = query.Count();
        DataTable dt = db.DataTable(query.ToString());

        // gets column names and put into array
        List<DataRow> list = dt.AsEnumerable().ToList();
        string[] columnList = dt.Columns.Cast<DataColumn>()
                             .Select(x => x.ColumnName)
                             .ToArray();
        var rowCount = dt.Rows.Count;
        var columnCount = dt.Columns.Count;

        for (var j = 0; j < rowCount; j++)
        {

            for (var i = 1; i < columnCount; i++) // skip ID column
            {
                var columnName = columnList[i];
                var data = list[j][i].ToString();
                lstName.Items.Add(columnName);
                lstData.Items.Add(data);
            }
        }

public static class DbContextExtensions
{
    public static DataTable DataTable(this DbContext context, string query)
    {
        DbProviderFactory dbFactory = DbProviderFactories.GetFactory(context.Database.Connection);

        using (var cmd = dbFactory.CreateCommand())
        {
            cmd.Connection = context.Database.Connection;
            cmd.CommandType = CommandType.Text;
            cmd.CommandText = query;
            using (DbDataAdapter adapter = dbFactory.CreateDataAdapter())
            {
                adapter.SelectCommand = cmd;

                DataTable dt = new DataTable();
                adapter.Fill(dt);

                return dt;
            }
        }
    }
}

我已经尝试了一些到 ObjectQuery、DBQuery 等的转换方法，但没有结果。我很困惑，需要一些指导。

Answer 1

我终于找到了我一直在寻找的答案！

https://www.c-sharpcorner.com/UploadFile/0c1bb2/convert-linq-query-result-to-datatable/

Entity Framework 6 和带有标量变量的 DBContext 或 DBQuery 或 DBSet 或 ObjectQuery

Entity Framework 6 and DBContext or DBQuery or DBSet or ObjectQuery with scalar variable

c#

entity-framework-6