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来自「以电子书的形式收集了VB一些常见问题解决方法,可以很方便的查找自己需要解决的问题」· HTML 代码 · 共 23 行

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    <title>Re: ADO &amp; NULL</title>
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      <h1>Re: ADO &amp; NULL</h1>
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Posted by <a href="mailto:luchen9999@yahoo.com">Tryit</a> on April 21, 1999 at 13:40:58:<p>
In Reply to: <a href="12227.html">ADO & NULL</a> posted by Ariel on April 21, 1999 at 08:47:37:<p>
: I have a procedure,I hope it can access from SQL with ADO,if a value of field<br>: is NULL,then it's be space,but I can only get the value first,after the first,<br>: I get NULL always.Why?<p>: Global cn As New ADODB.Connection<br>: Global quescmd As New ADODB.Command<br>: Global quesrec As New ADODB.Recordset<p>: Private Main()<br>:     Dim parm As ADODB.Parameter<br>:     Dim conn As String<br>:     <br>:     conn = "driver={SQL Server};server=ntserver1;uid=sa;pwd=;database=cbt"<br>:     With cn<br>:         .ConnectionString = conn<br>:         .ConnectionTimeout = 10<br>:         .Open<br>:     End With<br>:     <br>:     Set quescmd = New ADODB.Command<br>:     quescmd.ActiveConnection = cn<br>:     With quescmd<br>:         .CommandText = "select * from cbt_question where question_id=?"<br>:         .CommandType = adCmdText<br>:         .CommandTimeout = 15<br>:     End With<br>:     Set parm = New ADODB.Parameter<br>:     With parm<br>:         .Type = adChar<br>:         .Size = 8<br>:         .Direction = adParamInput<br>:         quescmd.Parameters.Append parm<br>:     End With<br>: End Sub<p>: Private Sub DispQues(quesid As String)<br>:     Dim i As Integer<br>:     Dim midstr As String<br>:     <br>:     quescmd.Parameters(0).Value = quesid<br>:     Set quesrec = quescmd.Execute()<br>:     <br>:     If quesrec.EOF = True Then<br>:         MsgBox "Not exist any question"<br>:         Exit Sub<br>:     End If<br>:     <br>:     QUESLABEL.Caption = quesrec!question_desc.GetChunk(200)   'All fields are Text in SQL<br>:     For i=1 To 3<br>' please modify this block as follow<br>'-------------------------<br>:       if IsNull(quesrec.fields(i).getchunk(200)) Then    'here is correct,it have a value<br>:           Label1(i).Caption=""<br>:       Else<br>:           Label1(i).Caption=quesrec.fields(i).getChunk(200)    'here prompt the value is NULL<br>:       Endif<br>'-------------------------<br>' new modify here begin<br>'***********************<br>        Label1(i).Caption- "" & quesrec.fields(i).getChunk(200)<br>' new modify here end<br>'***********************<p>:     Next i<br>: End Sub<p>
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