如何使用设计器中的bindingsource对象将数据正确绑定到组合框。 [英] How to correctly bind data to combobox using bindingsource object in the designer.

问题描述

你好：



我理解如何以编程方式将数据绑定到ComboBox：



例如：

Hello:

I understand how to bind data to a ComboBox programmatically:

For Example:

ComboBox1.DataSource = data.EmployeeList()
ComboBox1.DisplayMember = "Name"
ComboBox1.ValueMember = "EmployeeID"

但是，我试图做的是绑定数据使用设计器和绑定源对象。



如下所示，使用设计器我添加了数据源并配置了显示和值成员，但表单加载时没有数据。



如何使用设计器将列表绑定到Combobox？



我尝试过：



首先我创建了一个数据源：

However, what I am attempting to do is bind data using the designer and a Binding Source Object.

As demonstrated below, using the designer I added a data source and configured the display and value member but there is no data when the form loads.

How do I bind a list using the designer to a Combobox?

What I have tried:

First I created a Data Source:

Public Class Employee

    Public Property EmployeeID As String
    Public Property Name As String

End Class

Public Class Data

    Public Function Data() As List(Of Employee)

        Return New List(Of Employee)() From { _
         New Employee() With { _
          .Name = "George Benson", _
          .EmployeeID = 321
         }, _
         New Employee() With { _
          .Name = "Gladys Knight", _
          .EmployeeID = 322
         }, _
         New Employee() With { _
          .Name = "David Bowie", _
          .EmployeeID = 323
         }, _
         New Employee() With { _
          .Name = "Steve Wonder", _
          .EmployeeID = 324
         }, _
         New Employee() With { _
          .Name = "Tina Turner", _
          .EmployeeID = 325
         }
        }
    End Function

End Class

接下来我创建了一个带有一个只读属性的View Model，这样我就可以绑定

ComboBox吧。



注意：这不是MVP或MVPM的完全实现，这仅用于演示。

Next I created a View Model with a single read only property so that I can bind the
ComboBox to it.

Note: this is not full implementation of MVP Or MVPM, this is for demonstration only.

Public Class EmployeeViewModel

    Private _listEmployees As Data

    Sub New()
        _listEmployees = New Data()
    End Sub

    Public ReadOnly Property EmployeeList() As List(Of Employee)
        Get
            Return _listEmployees.Data()
        End Get
    End Property

End Class

推荐答案

我在一篇文章中有一个示例项目，用ListBox做你想做的事，但是ComboBox也是一样的：在C＃中使用JSON& VB [ ^ ]下载代码（v1.3）并查看VB版 WinFormSimpleCollection 项目。这是作为MVVM-esque应用程序完成的。它包括这个小帮助函数，用于将模型列表绑定到控件：

I have a sample project in an article that does what you want with a ListBox, but the ComboBox is just the same: Working with JSON in C# & VB[^] Download the code (v1.3) and look at the VB version of WinFormSimpleCollection project. This is done as a MVVM-esque app. It includes this little helper function for binding the list of models to the control:

Public Shared Sub BindList(Of TModel)(ctrl As ListControl, dataSource As IList(Of TModel), displayMember As String, valueMember As String)

    ctrl.DisplayMember = displayMember
    ctrl.ValueMember = valueMember
    ctrl.DataSource = dataSource

End Sub

< b>更新：这也可能有所帮助： c＃ - WinForms。设计时数据绑定到子控件的属性 - Stack Overflow [ ^ ]

Update: this may also be helpful: c# - WinForms. Design-time Data binding to child control's property - Stack Overflow[^]

这是一篇很好的文章，描述了绑定数据的几种方法：详细的数据绑定教程 [ ^ ]

Here is an excellent article describing several ways to bind data: A Detailed Data Binding Tutorial[^]

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