System.AccessViolationException关于文本框自动完成建议 [英] System.AccessViolationException On Textbox autocomplete suggestion

问题描述

我是vb.net上的新手

I am new on vb.net

我的问题是每当我想在自动填充建议上显示输入结果，项目中断并显示  

My Problem is whenever i want to show the typed result on autocomplete suggestion the project breaks and showing the   

抛出异常：System.Windows.Forms.dll中的'System.AccessViolationException'
$
System.Windows.Forms中出现未处理的类型'System.AccessViolationException'异常.dll

附加信息：尝试读取或写入受保护的内存。这通常表明其他内存已损坏。

Exception thrown: 'System.AccessViolationException' in System.Windows.Forms.dll
An unhandled exception of type 'System.AccessViolationException' occurred in System.Windows.Forms.dll
Additional information: Attempted to read or write protected memory. This is often an indication that other memory is corrupt.

我的代码是针对文本框更改的事件

My code are on changed event for Textbox

Private Sub txtTextProductChanged（sender as Object，e作为EventArgs）

        Dim txt = DirectCast（发件人，TextBox）

        'MsgBox（txt.Text）

        txt.Enabled = False

        Dim Accs As AutoCompleteStringCollection

        txt.AutoCompleteMode = AutoCompleteMode.None

        txt.AutoCompleteSource = AutoCompleteSource.None

        txt.AutoCompleteCustomSource.Clear（）



        txt.AutoCompleteMode = AutoCompleteMode.Suggest

        txt.AutoCompleteSource = AutoCompleteSource.CustomSource

       如果（Len（txt.Text）> 1）则为
            Accs = getProductName（txt.Text）

           如果Accs IsNot Nothing和Accs.Count> 0然后

                txt.AutoCompleteCustomSource = Accs

                Console.WriteLine（Accs.ToString）

           结束如果

       结束如果

        txt.Enabled = True

        txt.Focus（）

   结束子

Private Sub txtTextProductChanged(sender As Object, e As EventArgs)
        Dim txt = DirectCast(sender, TextBox)
        'MsgBox(txt.Text)
        txt.Enabled = False
        Dim Accs As AutoCompleteStringCollection
        txt.AutoCompleteMode = AutoCompleteMode.None
        txt.AutoCompleteSource = AutoCompleteSource.None
        txt.AutoCompleteCustomSource.Clear()

        txt.AutoCompleteMode = AutoCompleteMode.Suggest
        txt.AutoCompleteSource = AutoCompleteSource.CustomSource
        If (Len(txt.Text) > 1) Then
            Accs = getProductName(txt.Text)
            If Accs IsNot Nothing And Accs.Count > 0 Then
                txt.AutoCompleteCustomSource = Accs
                Console.WriteLine(Accs.ToString)
            End If
        End If
        txt.Enabled = True
        txt.Focus()
    End Sub

这是错误

尝试了所有但无法解决的问题

Tried every thing but Unable to solve it

请尽快帮助我项目

推荐答案

首先，TextBox的AutoComplete行为的定义不应该在Changed事件处理程序中。

First, the definition for the AutoComplete behavior of the TextBox should not be in the Changed event handler.

其次，你没有提供GetProductName函数，它是抛出错误的地方吗？

Second, you do not provide the GetProductName function, is it where the error is thrown?

第三，你的Try ... Catch在哪里？

Third, where are your Try...Catch?

至于代码：

- 在Load for example中构建你的AutoCompleteStringCollection：

-build up your AutoCompleteStringCollection in the Load for exemple:

 Private Sub Form1_Load(sender As Object, e As EventArgs) Handles MyBase.Load
        'Load into MySource all the words for the AutoComplete
        Dim MySource As New AutoCompleteStringCollection()

        MySource.AddRange(New String() _
                            {"January","February","March","April","May",
"June","July","August","September","October", "November","December"
                            })
        
        ' Initialize the text box.
        With TextBox1
            .AutoCompleteCustomSource = MySource
            .AutoCompleteMode = AutoCompleteMode.SuggestAppend
            .AutoCompleteSource = AutoCompleteSource.CustomSource
            .Location = New Point(20, 20)
            .Width = (Me.ClientRectangle.Width - 40) \ 2
            .Visible = True
        End With
    End Sub

这是你在提供的清单上有自动提示。

and that's it you have autosuggest on the list provided.

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