从读取Access数据库的OleDbDataReader中获取值

下面是我用来连接Access数据库并从查询中提取值的代码。 问题是..我无法从读者对象中获取任何值。 我可以看到有正确的行数，但是我一直得到一个InvalidOperationException（我是否使用GetValue（）或GetString（））说“行/列没有数据”。

System.Data.OleDb.OleDbConnection conn = new System.Data.OleDb.OleDbConnection(); conn.ConnectionString = @"Provider=Microsoft Office 12.0 Access Database Engine OLE DB Provider;" + @"Data source= C:\Users\nearod\Desktop\ImportDB.accdb"; try { conn.Open(); OleDbCommand cmd = new OleDbCommand("SELECT * FROM [SQL Agent Unique ID Test Load]", conn); OleDbDataReader reader = cmd.ExecuteReader(); string companyCode = reader.GetValue(0).ToString(); string agentId = reader.GetString(1); string firstName = reader.GetString(2); string lastName = reader.GetString(3); string nameSuffix = reader.GetString(4); string corporateName = reader.GetString(5); string entityType = reader.GetString(6); string obfSSN = reader.GetString(7); string obfFEIN = reader.GetString(8); string dummyIndicator = reader.GetString(9); // Insert code to process data. } catch (Exception ex) { MessageBox.Show("Failed to connect to data source"); } finally { conn.Close(); } 

Answer 1

你必须像下面这样调用Read方法（使用而不是处理你自己的连接

 string connectionString = @"Provider=Microsoft Office 12.0 Access Database Engine OLE DB Provider;" + @"Data source= C:\Users\nearod\Desktop\ImportDB.accdb"; string queryString= "SELECT * FROM [SQL Agent Unique ID Test Load]"; try { using (OleDbConnection connection = new OleDbConnection(connectionString)) { OleDbCommand command = new OleDbCommand(queryString, connection); connection.Open(); OleDbDataReader reader = command.ExecuteReader(); while (reader.Read()) { string companyCode = reader.GetValue(0).ToString(); string agentId = reader.GetString(1); string firstName = reader.GetString(2); string lastName = reader.GetString(3); string nameSuffix = reader.GetString(4); string corporateName = reader.GetString(5); string entityType = reader.GetString(6); string obfSSN = reader.GetString(7); string obfFEIN = reader.GetString(8); string dummyIndicator = reader.GetString(9); // Insert code to process data. } reader.Close(); } } catch (Exception ex) { MessageBox.Show("Failed to connect to data source"); } 

Answer 2

像这样修改你的代码：

 using (OleDbConnection connection = new OleDbConnection(connectionString)) { OleDbCommand command = new OleDbCommand(queryString, connection); connection.Open(); using (OleDbDataReader reader = command.ExecuteReader()) { while (reader.Read()) { string companyCode = reader.GetValue(0).ToString(); string agentId = reader.GetString(1); string firstName = reader.GetString(2); string lastName = reader.GetString(3); string nameSuffix = reader.GetString(4); string corporateName = reader.GetString(5); string entityType = reader.GetString(6); string obfSSN = reader.GetString(7); string obfFEIN = reader.GetString(8); string dummyIndicator = reader.GetString(9); // Insert code to process data. } } }