c# - 这些参数有什么问题？

Question

我有一个包含 7 个字段的 Access 文件:

DocID - text - primary
SourceID - text
ReceivedDay - Date/Time
Summary - text
DueDay - Date/Time
Person - text
Status - Yes/No

现在我想用下面的代码更新这个文件:

const string ConnectionString = "Provider=Microsoft.Jet.OLEDB.4.0;Data Source=|DataDirectory|\\DocMan.mdb;Persist Security Info=True";
const string InsertQuery = "INSERT Into Docs(DocID,ReceivedDay,Summary,Person,DueDay,Status,SourceID) Values(@DocID,@ReceivedDay,@Summary,@Person,@DueDay,@Status,@SourceID)";

string DocID = textBox1.Text;
string SourceID = comboBox1.SelectedIndex.ToString();
DateTime ReceivedDay = dateTimePicker1.Value;
string Summary = richTextBox1.Text;
string Person = textBox2.Text;
DateTime DueDay = dateTimePicker2.Value;
bool Status = false;

OleDbConnection cnn = new OleDbConnection(ConnectionString);
cnn.Open();
OleDbCommand cmd = new OleDbCommand(InsertQuery, cnn);
cmd.Parameters.AddWithValue("@DocID", DocID);
cmd.Parameters.AddWithValue("@SourceID", SourceID);
cmd.Parameters.AddWithValue("@ReceivedDay", ReceivedDay);
cmd.Parameters.AddWithValue("@Summary", Summary);
cmd.Parameters.AddWithValue("@Person", Person);
cmd.Parameters.AddWithValue("@DueDay", DueDay);
cmd.Parameters.AddWithValue("@Status", Status);
cmd.ExecuteNonQuery();
cnn.Close();

但我得到一个异常(exception):

Data type mismatch in criteria expression.

我该如何解决这个问题？

编辑:我用不同的方法解决了这个问题:

我构建了一个这样的查询:

INSERT INTO Docs
   (DocID, SourceID, ReceivedDay, Summary, Person, DueDay, Status)
VALUES (?, ?, ?, ?, ?, ?, ?)

然后使用 TableAdapter 调用它:

string DocID = textBox1.Text;

string SourceID = comboBox1.SelectedIndex.ToString();
DateTime ReceivedDay = dateTimePicker1.Value.Date;
string Summary = richTextBox1.Text;
string Person = textBox2.Text;
DateTime DueDay = dateTimePicker2.Value.Date;
bool Status = false;

DocManDataSetTableAdapters.DocsTableAdapter  docsTableAdapter = new DocManDataSetTableAdapters.DocsTableAdapter();
docsTableAdapter.InsertQuery(DocID,SourceID,ReceivedDay,Summary,Person,DueDay,false);

简单多了，而且现在工作正常。谢谢大家

Answer 1

简单ask google ，我想超过10000的点击率是相当可观的。你的论点“我不认为......”在你证明之前是无效的。

这就是MSDN说:

The OLE DB.NET Provider does not support named parameters for passing parameters to an SQL statement or a stored procedure called by an OleDbCommand when CommandType is set to Text. In this case, the question mark (?) placeholder must be used. For example:

SELECT * FROM Customers WHERE
CustomerID = ?

Therefore, the order in which OleDbParameter objects are added to the OleDbParameterCollection must directly correspond to the position of the question mark placeholder for the parameter in the command text.