vb.net - 传递参数时并非所有变量都绑定

Question

我尝试将值传递给数据适配器，但出现错误“并非所有变量都绑定”：

Dim strSql As String = "SELECT * FROM table WHERE A_DT>:a AND B_DT<:b"
Dim conn As New OleDb.OleDbConnection(strConn)
Dim datData As New OleDb.OleDbDataAdapter(strSql, CType(conn, OleDb.OleDbConnection))
Dim dtbdata As New DataTable
datData.SelectCommand.Parameters.Add(":a", OleDb.OleDbType.DBDate).Value = Date.Parse(A_Date)
datData.SelectCommand.Parameters.Add(":b", OleDb.OleDbType.DBDate).Value = Date.Parse(B_Date)
datData.Fill(dtbdata) '<--- Error happen in this line

Answer 1

请注意，OleDb 不支持命名参数，您需要使用“？” 而不是命名参数，然后按顺序传递参数，您的代码应如下所示：

Dim strSql As String = "SELECT * FROM table WHERE A_DT>? AND B_DT<?"
Dim conn As New OleDb.OleDbConnection(strConn)
Dim datData As New OleDb.OleDbDataAdapter(strSql, CType(conn, OleDb.OleDbConnection))
Dim dtbdata As New DataTable
datData.SelectCommand.Parameters.Add(New OleDb.OleDbParameter("@a", Date.Parse(A_Date)))
datData.SelectCommand.Parameters.Add(New OleDb.OleDbParameter("@b", Date.Parse(B_Date)))
datData.Fill(dtbdata)

如果您仍然坚持使用命名参数，我建议您改用SqlClient。