vb.net 为什么 ListView 不刷新？
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Why is ListView not refreshing?
提问by user1683987
Hi I am inserting into a table then reading everything back into a ListViewWhen I re-open the program I see the data I just saved in my ListView, but this record is not showing in my ListViewat the time of saving (although it is saved in the table).
嗨，我插入一个表格，然后读一切恢复到ListView当我重新打开这个程序我看我刚才保存在我的数据ListView，但这个纪录没有在我的显示ListView在节省的时间（虽然它被保存在桌子）。
I am using
我在用
listView.Update()
as well as
也
listView.Refresh()
but it does not seem to work. I am just using a SELECTquery to read data off the datareaderand store it in my listViewas follows (which is working properly)
但它似乎不起作用。我只是使用SELECT查询来读取数据datareader并将其存储在我的listView如下（工作正常）
The only problem is that the listView is not refreshing immediately, but it works when I close/open the program
唯一的问题是 listView 没有立即刷新，但是当我关闭/打开程序时它可以工作
here's the code I am using at the end of my Save method. basically these two methods get called
这是我在 Save 方法末尾使用的代码。基本上这两种方法被调用
Private Sub SetColumns()
Dim lstpenalty As New ListView()
lstpenalty.Items.Clear()
lstpenalty.Visible = True
lstpenalty.Bounds = New Rectangle(New Point(390, 55), New Size(560, 379))
lstpenalty.Name = "lstpenalty"
lstpenalty.FullRowSelect = True
lstpenalty.View = View.Details
lstpenalty.GridLines = True
lstpenalty.Items.Clear()
lstpenalty.Columns.Add("a", 75)
lstpenalty.Columns.Add("b", 70)
lstpenalty.Columns.Add("c", 105)
lstpenalty.Columns.Add("d", 98)
lstpenalty.Columns.Add("e", 90)
lstpenalty.Columns.Add("f", 105)
Me.Controls.Add(lstpenalty)
LoadPenaltyList(lstpenalty)
End Sub
Private Sub LoadPenaltyList(ByRef listView As ListView)
Dim gDR As OracleDataReader
Dim cmd As New OracleCommand
Dim lstpenaltyview As New ListViewItem
Try
cnn.Connect_to_Oper_Agent()
cmd.Connection = cnn.cnn
listView.Items.Clear()
cmd.CommandText = " select a," & _
"b, " & _
"c, " & _
"d," & _
"e," & _
"f" & _
" FROM myTable" & _
" commit"
gDR = cmd.ExecuteReader()
While gDR.Read
lstpenaltyview = listView.Items.Add(Null_To_String(gDR("a")))
lstpenaltyview.SubItems.Add(gDR("b"))
lstpenaltyview.SubItems.Add(gDR("c"))
lstpenaltyview.SubItems.Add(gDR("d"))
lstpenaltyview.SubItems.Add(gDR("e"))
lstpenaltyview.SubItems.Add(gDR("f"))
End While
listView.Update()
Catch ex As Exception
MsgBox("There was an error... -> " & ex.ToString)
Finally
cmd.Dispose()
cnn.Close_Conn()
End Try
End Sub
Thanks for your help
谢谢你的帮助
采纳答案by user1683987
So I was creating the ListView dynamically. The issue was that it kept creating ListViews over each other (memory leak), and it always showed the previous one. I created a static viewList versus a dynamic one and the issue is resolved:D
所以我正在动态创建 ListView。问题是它不断地相互创建 ListViews（内存泄漏），并且总是显示前一个。我创建了一个静态视图列表而不是动态视图列表，问题得到了解决：D
回答by stevepkr84
It is worth looking at what methods do.
值得看看方法是做什么的。
http://msdn.microsoft.com/en-us/library/system.windows.forms.listview_methods%28v=vs.71%29.aspx
http://msdn.microsoft.com/en-us/library/system.windows.forms.listview_methods%28v=vs.71%29.aspx
Update : Causes the control to redraw the invalidated regions within its client area.
更新：使控件重绘其客户区内的无效区域。
Refresh: Forces the control to invalidate its client area and immediately redraw itself and any child controls.
刷新：强制控件使其客户区无效并立即重绘自身和任何子控件。
To update it using table info, first Clear the listview, then redo the process you used to initially populate it.
要使用表信息更新它，首先清除列表视图，然后重做最初填充它时使用的过程。
回答by gonzalo
Use
用
For Each i As Windows.Forms.ListViewItem In ListView1.Items
i.Remove()
Next
Instead of Clear
代替 Clear
