VB6 ADODB.Recordset RecordCount 属性总是返回 -1 [英] VB6 ADODB.Recordset RecordCount property always returns -1

问题描述

我正在尝试让一些旧的 VB6 代码与 SQL Server Compact 一起使用.

I am trying to get some old VB6 code to work with SQL Server Compact.

我可以连接，打开数据库，一切似乎都很好.我可以运行有效的插入选择命令.

I can connect, open the database and all seems well. I can run insert select commands which work.

但是 ADODB.Recordset RecordCount 属性总是返回 -1，即使我可以访问字段并查看数据.更改 CursorLocation = adUseClient 会导致执行 SQL 时出现问题(多步操作产生错误).

However the ADODB.Recordset RecordCount property always returns -1 even though I can access the Fields and see the data. Changing the CursorLocation = adUseClient causes a problem when executung the SQL (multiple-step operation generated errors).

Option Explicit
    Private Const mSqlProvider          As String = "Provider=Microsoft.SQLSERVER.CE.OLEDB.3.5;"
    Private Const mSqlHost              As String = "Data Source=C:Database.sdf;"
    Private mCmd                        As ADODB.Command   ' For executing SQL
    Private mDbConnection               As ADODB.Connection


Private Sub Command1_Click()


   Dim rs As ADODB.Recordset

    Set rs = New ADODB.Recordset


    Dim DbConnectionString As String

    DbConnectionString = mSqlProvider & _
                            mSqlHost


    Set mDbConnection = New ADODB.Connection
    mDbConnection.CursorLocation = adUseServer

    Call mDbConnection.Open(DbConnectionString)

    If mDbConnection.State = adStateOpen Then
        Debug.Print (" Database is open")
        ' Initialise the command object
        Set mCmd = New ADODB.Command
        mCmd.ActiveConnection = mDbConnection

        mCmd.CommandText = "select * from myTestTable"
        mCmd.CommandType = adCmdText

        Set rs = mCmd.Execute

        Debug.Print rs.RecordCount  ' Always returns -1  !!
        Debug.Print rs.Fields(0)   ' returns correct data for first row, first col
        Debug.Print rs.Fields(1)   ' returns correct data for first row, 2nd col
        Debug.Print rs.Fields(2)   ' returns correct data for first row, 3rd col

    End If

End Sub

我们将不胜感激地接受任何建议.

Any advice would be gratefully accepted.

推荐答案

其实CursorLocation在这种情况下起了主要作用.使用 rs.CursorLocation = adUseClient 设置光标位置并试一试.

Actually the CursorLocation plays a major role in this case. Use rs.CursorLocation = adUseClient to set the cursor location and try.

    Set rs = New ADODB.Recordset
    rs.CursorLocation = adUseClient
    Dim DbConnectionString As String

    DbConnectionString = mSqlProvider & _
                            mSqlHost


    Set mDbConnection = New ADODB.Connection
    mDbConnection.CursorLocation = adUseServer

    Call mDbConnection.Open(DbConnectionString)

    If mDbConnection.State = adStateOpen Then
        Debug.Print (" Database is open")
        ' Initialise the command object
        Set mCmd = New ADODB.Command
        mCmd.ActiveConnection = mDbConnection

        mCmd.CommandText = "select * from myTestTable"
        mCmd.CommandType = adCmdText

        Set rs = mCmd.Execute

        Debug.Print rs.RecordCount  ' This should now return the right value.
        Debug.Print rs.Fields(0)   ' returns correct data for first row, first col
        Debug.Print rs.Fields(1)   ' returns correct data for first row, 2nd col
        Debug.Print rs.Fields(2)   ' returns correct data for first row, 3rd col

    End If

End Sub

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