如何根据数据库表查询 C# 列表

Question

当我传递列表的字符串版本时，我的代码不会从测试数据库表返回任何行，但如果我直接传递列表成员，它会返回行。

当我使用消息框显示字符串 joinedSerialsList 时，它的格式似乎正确。

// Create comma delimited list of serials:

int currentSerial = beginning;

List<string> serialsList = new List<string>();

for (int i = 0; i < count; i++)

{

     serialsList.Add(currentSerial.ToString());

     currentSerial++;

}

string joinedSerialsList = string.Format("({0})", string.Join(", ", serialsList));

OleDbConnection connection = BadgeDatabaseDB.GetConnection();

string checkStatement

     = "SELECT SerialNumber, OrderNumber "

     + "FROM SerialNumbersMFG "

     + "WHERE SerialNumber IN (@List)";

OleDbCommand command = new OleDbCommand(checkStatement, connection);

command.Parameters.AddWithValue("@List", joinedSerialsList);

string duplicateSerials = "";

try

{

    connection.Open();

    OleDbDataReader dataReader = command.ExecuteReader();

    if (dataReader.Read())

    {

        duplicateSerials += dataReader["OrderNumber"].ToString() + "\n";

    }

}

catch (OleDbException ex)

    {

        throw ex;

    }

finally

    {

        connection.Close();

    }

return duplicateSerials;

Answer 1

我重写了你的样本，这项工作：&nbsp; &nbsp; private IEnumerable<string> getData()&nbsp; &nbsp; {&nbsp; &nbsp; &nbsp; &nbsp; // Create comma delimited list of serials:&nbsp; &nbsp; &nbsp; &nbsp; int currentSerial = 4452; // your constant&nbsp; &nbsp; &nbsp; &nbsp; var serialsList = new List<int>();&nbsp; &nbsp; &nbsp; &nbsp; var count = 100;&nbsp; &nbsp; &nbsp; &nbsp; for (int i = 0; i < count; i++)&nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; serialsList.Add(currentSerial++);&nbsp; &nbsp; &nbsp; &nbsp; var connString = getConnectionString();&nbsp; &nbsp; &nbsp; &nbsp; var results = new List<string>();&nbsp; &nbsp; &nbsp; &nbsp; string sqlSelect = $"SELECT SerialNumber, OrderNumber FROM SerialNumbersMFG WHERE SerialNumber IN ({string.Join(",", serialsList)})";&nbsp; &nbsp; &nbsp; &nbsp; using (var connection = new SqlConnection(connString)) // BadgeDatabaseDB.GetConnection();&nbsp; &nbsp; &nbsp; &nbsp; {&nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; using (var command = new SqlCommand(sqlSelect, connection))&nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; {&nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; connection.Open();&nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; var dataReader = command.ExecuteReader();&nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; while (dataReader.Read())&nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; results.Add(dataReader["OrderNumber"].ToString());&nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; }&nbsp; &nbsp; &nbsp; &nbsp; }&nbsp; &nbsp; &nbsp; &nbsp; return results;&nbsp; &nbsp; }