var reader = cmd.ExecuteReader();

var columns = new List<string>();

for(int i=0;i<reader.FieldCount;i++)
{
   columns.Add(reader.GetName(i));
}

or

var columns = Enumerable.Range(0, reader.FieldCount).Select(reader.GetName).ToList();

在SqlDataReader上有一个GetName函数，它接受列索引并返回列的名称。

相反，有一个GetOrdinal，它接受列名并返回列索引。

在SQL中更容易实现

var columnsList = dbContext.Database.SqlQuery<string>("SELECT COLUMN_NAME FROM INFORMATION_SCHEMA.COLUMNS WHERE TABLE_SCHEMA = 'SCHEMA_OF_YOUE_TABLE' AND TABLE_NAME = 'YOUR_TABLE_NAME'").ToList();

您可以从DataReader中获取列名。

下面是最重要的部分:

  for (int col = 0; col < SqlReader.FieldCount; col++)
  {
    Console.Write(SqlReader.GetName(col).ToString());         // Gets the column name
    Console.Write(SqlReader.GetFieldType(col).ToString());    // Gets the column type
    Console.Write(SqlReader.GetDataTypeName(col).ToString()); // Gets the column database type
  }

如果你只想要列名，你可以这样做:

List<string> columns = new List<string>();
using (SqlDataReader reader = cmd.ExecuteReader(CommandBehavior.SchemaOnly))
{
    DataTable dt = reader.GetSchemaTable();
    foreach (DataRow row in dt.Rows)
    {
        columns.Add(row.Field<String>("ColumnName"));
    }
}

但如果只需要一行，我喜欢添加的AdoHelper。如果你有一个单行查询，你不想在你的代码中处理数据表，这个添加是伟大的。它返回一个不区分大小写的列名和值字典。

public static Dictionary<string, string> ExecuteCaseInsensitiveDictionary(string query, string connectionString, Dictionary<string, string> queryParams = null)
{
    Dictionary<string, string> CaseInsensitiveDictionary = new Dictionary<string, string>(StringComparer.OrdinalIgnoreCase);
    try
    {
        using (SqlConnection conn = new SqlConnection(connectionString))
        {
            conn.Open();
            using (SqlCommand cmd = new SqlCommand())
            {
                cmd.Connection = conn;
                cmd.CommandType = CommandType.Text;
                cmd.CommandText = query;

                // Add the parameters for the SelectCommand.
                if (queryParams != null)
                    foreach (var param in queryParams)
                        cmd.Parameters.AddWithValue(param.Key, param.Value);

                using (SqlDataReader reader = cmd.ExecuteReader())
                {
                    DataTable dt = new DataTable();
                    dt.Load(reader);
                    foreach (DataRow row in dt.Rows)
                    {
                        foreach (DataColumn column in dt.Columns)
                        {
                            CaseInsensitiveDictionary.Add(column.ColumnName, row[column].ToString());
                        }
                    }
                }
            }
            conn.Close();
        }
    }
    catch (Exception ex)
    {
        throw ex;
    }
    return CaseInsensitiveDictionary;
}

使用扩展方法:

    public static List<string> ColumnList(this IDataReader dataReader)
    {
        var columns = new List<string>();
        for (int i = 0; i < dataReader.FieldCount; i++)
        {
            columns.Add(dataReader.GetName(i));
        }
        return columns;
    }