将文本框绑定到使用LINQ to XML数据填充的组合框 [英] Binding Text Box to Combo Box populated with LINQ to XML data

问题描述

我无法弄清楚如何正确地将TextBox绑定到一个ComboBox，该ComboBox使用以下结构的XML文件填充数据：

I'm having trouble figuring out how to properly bind TextBoxes to a ComboBox that is populated with data from an XML file with the following structure:

<?xml version="1.0" encoding="utf-8"?>
<CustDB xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance">
  <Customer>
    <Name />
    <Address1 />
    <Address2 />
    <Phone />
    <Fax />
    <Cell />
    <Other />
    <Attn />
    <Email />
    <SalesPerson />
  </Customer>
</CustDB>

我的绑定是通过LINQ to XML完成的：

My binding is done through LINQ to XML:

Dim dbXML As String = "..\custdbTesting.xml"
        Dim contacts = XDocument.Load(dbXML, LoadOptions.PreserveWhitespace)
        Dim custQuery = From customer In contacts.Elements("CustDB").Elements("Customer") _
                        Order By customer.Value Ascending _
                        Select Nm = customer.Elements("Name").Value, Ad1 = customer.Elements("Address1").Value, Ad2 = customer.Elements("Address2").Value _
                        , Ph = customer.Elements("Phone").Value, Fx = customer.Elements("Fax").Value, Ce = customer.Elements("Cell").Value _
                        , Oth = customer.Elements("Other").Value, Atn = customer.Elements("Attn").Value, Eml = customer.Elements("Email").Value _
                        , SaPe = customer.Elements("SalesPerson").Value

        For Each result In custQuery
            cbxName.Items.Add(result.Nm)
        Next

<ComboBox x:Name="cbxName"/>
<TextBox x:Name="txbAdd1" Margin="0,23,0,0" Text="{Binding SelectedItem, ElementName=cbxName}"/>

有人可以帮我弄清楚我做错了什么吗？我正在使用Visual Studio 2012并通过TextBox属性docker添加绑定。我认为这是直截了当的，但不是这样。

Can someone please help me figure out what I am doing wrong? I am using Visual Studio 2012 and adding binding through the TextBox properties docker. I assumed this would be straight forward, but not so.

推荐答案

要做的步骤：

1）创建课程：

Steps to do:
1) Create class:

Public Class Customer

    Private sName As String = String.Empty
    Private sAddress1 As String = String.Empty
    Private sAddress2 As String = String.Empty
    Private sPhone As String = String.Empty
    Private sFax As String = String.Empty
    Private sCell As String = String.Empty
    Private sOther As String = String.Empty
    Private sAttn As String = String.Empty
    Private sEmail As String = String.Empty
    Private sSalesPerson As String = String.Empty

    Public Property CustName As String
        Get
            Return sName
        End Get
        Set(value As String)
            sName = value
        End Set
    End Property

    Public Property Address1 As String
        Get
            Return sAddress1
        End Get
        Set(value As String)
            sAddress1 = value
        End Set
    End Property

    Public Property Address2 As String
        Get
            Return sAddress2
        End Get
        Set(value As String)
            sAddress2 = value
        End Set
    End Property

    Public Property Phone As String
        Get
            Return sAddress2
        End Get
        Set(value As String)
            sAddress2 = value
        End Set
    End Property

    Public Property Fax As String
        Get
            Return sFax
        End Get
        Set(value As String)
            sFax = value
        End Set
    End Property

    Public Property Cell As String
        Get
            Return sCell
        End Get
        Set(value As String)
            sCell = value
        End Set
    End Property

    Public Property Other As String
        Get
            Return sOther
        End Get
        Set(value As String)
            sOther = value
        End Set
    End Property

    Public Property Attn As String
        Get
            Return sAttn
        End Get
        Set(value As String)
            sAttn = value
        End Set
    End Property

    Public Property Email As String
        Get
            Return sEmail
        End Get
        Set(value As String)
            sEmail = value
        End Set
    End Property

    Public Property SalesPerson As String
        Get
            Return sSalesPerson
        End Get
        Set(value As String)
            sSalesPerson = value
        End Set
    End Property


End Class

此类与xml结构具有相同的成员。



2）创建新界面以便能够使用类属性

This class has the same members as your xml structure.

2) Create new Interface to be able to use class properties

Public Interface ICustomer
    'properties
    Property Name As String
    Property Address1 As String
    Property Address2 As String
    Property Phone As String
    Property Fax As String
    Property Cell As String
    Property Other As String
    Property Attn As String
    Property Email As String
    Property SalesPerson As String

End

了解有关界面的更多信息[ ^ ]



3）添加新模块。定义全局变量 Customers ，其中包含 Customer 的列表。创建过程/子例程以将数据从xml加载到 Customers 列表中。

Read more about Interfaces[^]

3) Add new module. Define global variable Customers which holds the list of Customer. Create procedure/subroutine to load data from xml into Customers list.

Module ModMain

    Public Customers As List(Of Customer) = Nothing

    Sub LoadXmlData(sFileName As String)
        Dim xDoc As XDocument = Nothing
        Dim custList As IEnumerable = Nothing
        Try

            Customers = New List(Of Customer)
            xDoc = XDocument.Load(sFileName, LoadOptions.PreserveWhitespace)
            custList = From customer In xdoc.Elements("CustDB").Elements("Customer") _
                            Order By customer.Value Ascending _
                            Select Nm = customer.Elements("Name").Value, Ad1 = customer.Elements("Address1").Value, Ad2 = customer.Elements("Address2").Value _
                            , Ph = customer.Elements("Phone").Value, Fx = customer.Elements("Fax").Value, Ce = customer.Elements("Cell").Value _
                            , Oth = customer.Elements("Other").Value, Atn = customer.Elements("Attn").Value, Eml = customer.Elements("Email").Value _
                            , SaPe = customer.Elements("SalesPerson").Value

            For Each c In custList
                Dim cu As Customer = New Customer
                With cu
                    .CustName = c.Nm
                    .Address1 = c.Ad1
                    .Address2 = c.Ad2
                    .Phone = c.Ph
                    .Fax = c.Fx
                    .Cell = c.Ce
                    .Other = c.Oth
                    .Attn = c.Atn
                    .Email = c.Eml
                    .SalesPerson = c.SaPe
                End With
                Customers.Add(cu)
            Next

        Catch ex As Exception
            MsgBox(ex.Message, MsgBoxStyle.Exclamation, "Error...")

        Finally
            xDoc = Nothing
        End Try
    End Sub

End Module

请参阅： IEnumerable Interface [ ^ ]



4）点击此链接了解如何创建绑定上下文。

WPF中的简单数据绑定 [ ^ ] - 第2步

See: IEnumerable Interface[^]

4) follow this link to find out how to create binding context.
Simple Data Binding in WPF[^] - step 2

<TextBox Text="{Binding CustName}" Margin="10" Grid.Column="1"></TextBox>

CP KB更多内容：

WPF中数据绑定的一个非常简单的例子 [ ^ ]

WPF数据绑定 - 第1部分 [ ^ ]



5）最后，使用以下代码：

More at CP KB:
A Very Simple Example of Data Binding in WPF[^]
WPF Data Binding - Part 1[^]

5) Finally, use this code:

Class MainWindow
    ' on combobox selection change
    Private Sub CustCombo_SelectionChanged(sender As Object, e As SelectionChangedEventArgs)
        Try
            Dim cmb As ComboBox = sender
            Dim i As Integer = cmb.SelectedIndex
            Dim cust As Customer = Customers(i)
            Me.DataContext = cust

        Catch ex As Exception
            MsgBox(ex.Message, MsgBoxStyle.Exclamation, "Error...")
        End Try
    End Sub

    'new instance of window/application
    Public Sub New()

        ' This call is required by the designer.
        InitializeComponent()

        ' Add any initialization after the InitializeComponent() call.
        'call LoadXmlData to fill global variable Customer as a List(of Customer)
        Dim sFileName As String = "D:\custdbTesting.xml"
        LoadXmlData(sFileName)
        'fill combobox with customer names
        For Each c As Customer In Customers
            Me.CustCombo.Items.Add(c.CustName)
        Next


    End Sub

End Class

注意： 这是非常基本的样本。还有很多需要改进的地方，例如：您可以通过 xml序列化 [ ^ ]。

自定义类集合序列化和反序列化的完整示例 [ ^ ]



您可以在这里下载 [^] 一个完整的样本（不含xml）。



And最重要的：我强烈建议阅读 MSDN文档 [ ^ ]。

Note: This is very basic sample. There's a lot to improve, for example: you can load data from xml to class via xml serialization[^].
A Complete Sample of Custom Class Collection Serialization and Deserialization[^]

Here you can download[^] a complete sample (without xml).

And the most important: i strongly recommend to read MSDN documentation[^].

你在哪里调用数据加载代码？

我复制了你所有的代码，它就像一个魅力。当然我修改了文件路径，但我认为路径没问题，考虑到路径错误时会出现异常。



顺便问一下，是有没有机会错误地引用另一个 custdbTesting.xml 而不是你想要的那个？看来，你从目录项目目录/ bin 中的文件中读取。



我调用数据加载，当MainWindow是已加载：

Where do you call the data loading code?
I have copied all your code and it worked like a charm. Naturally I modified the file path, but I suppose that the path is OK for you, considering that an exception appear when you have wrong path.

By the way, is there any chance that by mistake you are referencing another custdbTesting.xml and not the one you want? It seems, that you read from a file that is in directory project directory/bin.

I call data loading, when the MainWindow is loaded:

<window x:class="MainWindow" xmlns:x="#unknown">
        ...
        Loaded="Window_Loaded_1">
...
<!-- UI element definitions -->
</window>

和后面的代码：

and the code behind:

Private Sub Window_Loaded_1(sender As Object, e As RoutedEventArgs)
        Dim dbXML As String = "../../custdbTesting.xml"
        ' File path to my test file in project folder
        ' Rest is the same you wrote
        ...
End Sub

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