编辑源数据后更新/刷新列表框

Question

I would like to create in PowerShell a Windows form that uses a ListBox that selects data for editing. As an entry in the ListBox is selected, textboxes below are bound to properties in the selected entry, allowing the editing of that entry. Sounds simple, and almost is, if only the ListBox would always show the current state of the data.

A stripped down version of the code produces a form that looks like this image below. The textboxes at the bottom of the form appear to work perfectly, that is, the test I've done show the bound data is changing as you type in them. But the content of the ListBox is never refreshed or updated, and so far all attempts at fixing this seem to either not work, cause other problems.

Initially I was creating a class in PowerShell for holding the data, but switched to a C# class:

Add-Type -ReferencedAssemblies "System.Windows.Forms" -Language CSharp -TypeDefinition @'
using System;
public class VectorData {
    double _degrees = 0.0d;
    double _distance = 0.0d;
    public double Degrees {
        get {
            return this._degrees;
        }
        set {
            this._degrees = value;
        }
    }
    public double Distance {
        get {
            return this._distance;
        }
        set {
            this._distance = value;
        }
    }
    public string Display {
        get {
            return "" + this._degrees + "\u00B0 \u2192 " + this._distance + "\u0027";
        }
    }
    public VectorData(double degrees, double distance){
        this._degrees = degrees;
        this._distance = distance;
    }
}
'@

I've tried all three of these examples for creating the list that can be bound to the ListBox, but none of them update the ListBox's content as the data changes.

#$Vectors = [System.Collections.Generic.List[VectorData]]::new()
$Vectors = [System.ComponentModel.BindingList[VectorData]]::new()
#$Vectors = [System.Collections.ObjectModel.ObservableCollection[VectorData]]::new()

This is the core code, $lbxVectors is the ListBox. $tbxDegrees and $tbxDistance are textboxes.

function SetVectorsDataSource {
    $lbxVectors.DataSource = $null
    $lbxVectors.DataSource = $Vectors
    $lbxVectors.DisplayMember = 'Display'
}
function BindTextBoxes {
    $VD = $Vectors[$lbxVectors.SelectedIndex]
    $null = $txbDegrees.DataBindings.Clear()
    $null = $txbDegrees.DataBindings.Add('Text', $VD, "Degrees")
    $null = $txbDistance.DataBindings.Clear()
    $null = $txbDistance.DataBindings.Add('Text', $VD, "Distance")
}

$null = $Vectors.Add([VectorData]::new(45, 20))
$null = $Vectors.Add([VectorData]::new(193, 32))
$null = $Vectors.Add([VectorData]::new(155, 18))
SetVectorsDataSource
BindTextBoxes
$lbxVectors.Add_SelectedIndexChanged({
    BindTextBoxes
})

Calling the SetVectorsDataSource function from the textboxes' TextChanged event seems to overwrite what you type with the original data, so that doesn't work:

$txbDegrees.Add_TextChanged({
#   SetVectorsDataSource
})
$txbDistance.Add_TextChanged({
#   SetVectorsDataSource
})

So, does anyone have any idea on how to keep the ListBox up-to-date with the current state of the data?

FYI: Here is the full code if someone wants to try it:

using namespace System.Windows.Forms
Add-Type -AssemblyName System.Windows.Forms

Add-Type -ReferencedAssemblies "System.Windows.Forms" -Language CSharp -TypeDefinition @'
using System;
public class VectorData {
    double _degrees = 0.0d;
    double _distance = 0.0d;
    public double Degrees {
        get {
            return this._degrees;
        }
        set {
            this._degrees = value;
        }
    }
    public double Distance {
        get {
            return this._distance;
        }
        set {
            this._distance = value;
        }
    }
    public string Display {
        get {
            return "" + this._degrees + "\u00B0 \u2192 " + this._distance + "\u0027";
        }
    }
    public VectorData(double degrees, double distance){
        this._degrees = degrees;
        this._distance = distance;
    }
}
'@
#$Vectors = [System.Collections.Generic.List[VectorData]]::new()
$Vectors = [System.ComponentModel.BindingList[VectorData]]::new()
#$Vectors = [System.Collections.ObjectModel.ObservableCollection[VectorData]]::new()

#region Build form and controls
    function NextCtrlY { param ( [Control]$Control ) return $Control.Location.Y + $Control.Size.Height }

    $ClientWidth = 200
    $lbxVectors = [ListBox]@{
        Location = "12, 12"
        Name = "lbxVectors"
        Size = "$($ClientWidth - 24), 120"
        TabIndex = 0
    }

    $TextBoxWidth = ($ClientWidth - (12 + 6 + 12))/2
    $LeftTxBxX = 12 + $TextBoxWidth + 6
    $lblDegrees = [Label]@{
        AutoSize = $true
        Location = "12, $(NextCtrlY $lbxVectors)"
        Name = "lblDegrees"
        TabIndex = 1
        Text = "Degrees:"
    }

    $lblDistance = [Label]@{
        AutoSize = $true
        Location = "$LeftTxBxX, $(NextCtrlY $lbxVectors)"
        Name = "lblDistance"
        TabIndex = 2
        Text = "Distance:"
    }

    $txbDegrees = [TextBox]@{
        Location = "12, $(NextCtrlY $lblDegrees)"
        Name = "txbDegrees"
        Size = "$TextBoxWidth, 20"
        TabIndex = 3
        Text = ""
    }

    $txbDistance = [TextBox]@{
        Location = "$LeftTxBxX, $($txbDegrees.Location.Y)"
        Name = "txbDistance"
        Size = "$TextBoxWidth, 12"
        TabIndex = 4
        Text = ""
    }

    $ListBoxTestForm = [Form]@{
        ClientSize = "$ClientWidth, $($(NextCtrlY $txbDegrees) + 12)"
        FormBorderStyle = 'FixedDialog'
        MaximizeBox = $false
        MinimizeBox = $true
        Name = 'ListBoxTestForm'
        StartPosition = 'CenterScreen'
        Text = "ListBox Test"
    }

    $ListBoxTestForm.Controls.Add($lbxVectors)
    $ListBoxTestForm.Controls.Add($lblDegrees)
    $ListBoxTestForm.Controls.Add($lblDistance)
    $ListBoxTestForm.Controls.Add($txbDegrees)
    $ListBoxTestForm.Controls.Add($txbDistance)
#endregion


function SetVectorsDataSource {
    $lbxVectors.DataSource = $null
    $lbxVectors.DataSource = $Vectors
    $lbxVectors.DisplayMember = 'Display'
}
function BindTextBoxes {
    $VD = $Vectors[$lbxVectors.SelectedIndex]
    $null = $txbDegrees.DataBindings.Clear()
    $null = $txbDegrees.DataBindings.Add('Text', $VD, "Degrees")
    $null = $txbDistance.DataBindings.Clear()
    $null = $txbDistance.DataBindings.Add('Text', $VD, "Distance")
}

$null = $Vectors.Add([VectorData]::new(45, 20))
$null = $Vectors.Add([VectorData]::new(193, 32))
$null = $Vectors.Add([VectorData]::new(155, 18))
SetVectorsDataSource
BindTextBoxes
$lbxVectors.Add_SelectedIndexChanged({
    BindTextBoxes
})

$txbDegrees.Add_TextChanged({
#   SetVectorsDataSource
})
$txbDistance.Add_TextChanged({
#   SetVectorsDataSource
})

$null = $ListBoxTestForm.ShowDialog()

Answer 1

As I was about to post this question, I looked at the list of "Similar questions" and found this C# question/answer .

Replaced the core code with the following and it works::

$VectorBindingSource = [BindingSource]::new()
$VectorBindingSource.DataSource = $Vectors

$lbxVectors.DataSource = $VectorBindingSource
$lbxVectors.DisplayMember = "Display"
$lbxVectors.ValueMember = "Display"

$null = $txbDegrees.DataBindings.Add("Text", $VectorBindingSource, "Degrees", $true, [DataSourceUpdateMode]::OnPropertyChanged)
$null = $txbDistance.DataBindings.Add("Text", $VectorBindingSource, "Distance", $true, [DataSourceUpdateMode]::OnPropertyChanged)
$null = $Vectors.Add([VectorData]::new(45, 20))
$null = $Vectors.Add([VectorData]::new(193, 32))
$null = $Vectors.Add([VectorData]::new(155, 18))

NOTE: Requires BindingList, doesn't work with generic list or ObservableCollection:

$Vectors = [System.ComponentModel.BindingList[VectorData]]::new()