[英]Entity Framework 6 and DBContext or DBQuery or DBSet or ObjectQuery with scalar variable
I'm trying to pass a variable to my DBContext extension.我正在尝试将变量传递给我的 DBContext 扩展。 It works fine with a fixed string but when I try to use a variable I get the error "Must declare the scalar variable @p_linq_0"
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;
}
}
}
}
I've tried a few conversion methods to ObjectQuery, DBQuery, etc with no result.我尝试了一些转换为 ObjectQuery、DBQuery 等的方法,但没有结果。 I'm so confused need some direction please.
我很困惑,需要一些方向。
I finally found the answer I was looking for!我终于找到了我想要的答案!
https://www.c-sharpcorner.com/UploadFile/0c1bb2/convert-linq-query-result-to-datatable/ https://www.c-sharpcorner.com/UploadFile/0c1bb2/convert-linq-query-result-to-datatable/
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