Question

我创建了一个非常简单的表单，其中包含两个文本框和一个“更新位置”按钮，其输入值应更新为数据库中的两个链接表。我最终试图把它放在一个独立的应用程序中，但是现在我只想让表单本身工作。我是FoxPro的新手，所以我不知道是否有可能只是一个表单更新我的表，或者是否有其他问题在工作。

这是我的“更新位置”按钮的代码（OldLoc是第一个文本框，NewLoc是第二个）：

SET DATABASE TO LOCATIONS
CLOSE ALL DATABASES
OPEN DATABASE locations\locations EXCLUSIVE

IF  this.parent.OldLoc.Value == "" then  
     MESSAGEBOX('Please fill in the old location.', 48, 'Missing Location Information')
this.parent.OldLoc.SetFocus

ELSE
INDEX ON table1.loc TAG loc
SET ORDER TO loc
SEEK this.parent.OldLoc.Value IN table1

IF FOUND()
    IF this.parent.NewLoc.Value == "" then
        MESSAGEBOX('Please fill in the new location.', 48, 
                                 'Missing  Location Information')       this.parent.NewLoc.SetFocus  

    UPDATE table1 SET loc = this.parent.NewLoc.Value ; 
                   WHERE loc = this.parent.OldLoc.value
    UPDATE table2 SET loc = this.parent.NewLoc.Value ;
                   WHERE loc = this.parent.OldLoc.value

    ENDIF
ENDIF
ENDIF

您对任何输入表示赞赏！

my very basic form

Answer 1

你在点击事件中做了多余的工作......关闭数据库，然后重新打开，然后打开独占。您尝试更新的表应该已经有了您计划加入或搜索的键列的索引。完成后，您不需要反复显式创建索引标记...一旦创建了索引“TAG”，您就不需要再做了..

所以，那就是说......

打开表单，然后打开“INIT”事件。在那里，您可以在表单正在使用时显式打开表格以供使用...

IF NOT DBUSED( "Locations" )
   */ You only need exclusive if you will be modifying the database.
   */ The indexes should already exist before the form ever starts
   Open Database Locations\Locations SHARED
ENDIF

现在，您的更新按钮的“点击”事件...预先确认有值，不要担心尝试寻找或更新，除非填写完... ...

IF    ALLTRIM( This.Parent.OldLoc.Value ) == "";
   OR ALLTRIM( This.Parent.NewLoc.Value ) == ""
   */ Simple one message about BOTH being required
   messagebox( "Please fill in both Old and New Locations.", 48, ;
      "Missing Location Information" )
ENDIF

*/ Then, update... if no entries match, no records will be updated.
*/ VFP sometimes chokes with multiple "." values such as form values 
*/ as SQL commands are expecting "alias.field" format... 
lcOldValue = This.Parent.OldLoc.Value
lcNewValue = This.Parent.NewLoc.Value


Update Locations!Table1;
   set Loc = lcNewLoc;
   where Loc = lcOldLoc

*/ Were there any updates?
llAnyUpdates = _Tally > 0

*/ Now, the OTHER table too...
Update Locations!Table1;
   set Loc = lcNewLoc;
   where Loc = lcOldLoc

*/ Were there any updates on THIS cycle...
llAnyUpdates = llAnyUpdates OR _Tally > 0

if llAnyUpdates
   messagebox( "Locations have been updated.", 0, "Update complete" )
else
   messagebox( "No such location found to be updated.", 0, "No Records Updated" )
endif

Answer 2

您可能还想查看表单的数据环境。您可以选择在表单加载时打开表单的表格，这样可以在表单加载事件或表单init事件中明确打开它们

我对“更新位置”按钮的点击事件的简单提议是： -

LOCAL lcOldLoc,lcNewLoc
WITH THISFORM
    lcOldLoc=.oldloc.VALUE
    lcNewLoc=newloc.VALUE
    DO CASE
        CASE EMPTY(lcOldLoc)
            MESSAGEBOX("PLEASE ENTER OLD LOCATION",16,"ERROR")
        CASE EMPTY(lcNewLoc)
            MESSAGEBOX("NEW LOCATION CAN'T BE EMPTY",16,"ERROR")
        OTHERWISE
            UPDATE table1 SET loc=lcNewLoc WHERE loc=lcOldLoc
            DO CASE
                CASE _TALLY=0
                    MESSAGEBOX("OLD LOCATION NOT FOUND",16,"ERROR")
                OTHERWISE
                    UPDATE tabel2 SET loc=lcNewLoc WHERE loc=lcOldLoc
            ENDCASE
    ENDCASE
ENDWITH

这应该是唯一需要的代码。显然，可以对上述内容进行许多改进，但实质上可以完成这项工作。

如果您想从头开始构建上述表单，请发送电子邮件至support@foxsoft.co.uk，我将为您提供现场演示。

FoxPro表单不更新表

2 个答案: