英文:
How do I create individual event handlers for buttons added dynamically to a WinForm in Powershell
问题
我正在尝试创建一个动态生成的 WinForm，其中我传递一个包含名称（键）和图像托管的 URL（值）的字典。
代码会遍历字典并为每个“键”添加一个按钮，当按钮被按下时，它会将图片框设置为该按钮对应的 URL 上的图像。
每次都可能有不同数量的按钮（最多可能达到 10 个）。
我不确定我的方法是否正确，但我得到了我想要的大部分内容。问题在于，不管按下哪个按钮，图像始终是“Mason”。
Add-Type -AssemblyName System.Windows.Forms# 定义名称和图像 URL 的字典$image_url_lookup = @{'Eric' = 'https://cdn.images.express.co.uk/img/dynamic/67/285x190/1758705_1.jpg''Mason' = 'https://cdn.images.express.co.uk/img/dynamic/67/285x190/1758732_1.jpg''Other' = 'https://cdn.images.express.co.uk/img/dynamic/67/285x190/1758699_1.jpg'}# 创建一个新窗体$form = New-Object System.Windows.Forms.Form$form.Text = "Select Images"$form.Width = 800$form.Height = 600$form.BackColor = [System.Drawing.Color]::White# 创建一个新表格布局面板$tableLayoutPanel = New-Object System.Windows.Forms.TableLayoutPanel$tableLayoutPanel.Dock = [System.Windows.Forms.DockStyle]::Fill# 创建一个新图片框$pictureBox = New-Object System.Windows.Forms.PictureBox$pictureBox.Width = $form.Width - 100$pictureBox.Height = $form.Height - 100$pictureBox.Left = ($form.Width - $pictureBox.Width) / 2$pictureBox.Top = ($form.Height - $pictureBox.Height) / 2$pictureBox.BackColor = [System.Drawing.Color]::Transparent$pictureBox.SizeMode = [System.Windows.Forms.PictureBoxSizeMode]::Zoom$image_index = 0foreach ($name in $image_url_lookup.Keys) {$image_index++$button = New-Object System.Windows.Forms.Button$button.Name = "Button$image_index"$button.Text = $name$button.AccessibleName = $image_url_lookup[$name]$button.Add_Click({ $pictureBox.ImageLocation = $button.AccessibleName })$button.Width = 75$button.Height = 23# 将按钮添加到表格布局面板$tableLayoutPanel.Controls.Add($button, $i, 0)}# 将图片框添加到表格布局面板$tableLayoutPanel.Controls.Add($pictureBox, 0, 1)$tableLayoutPanel.SetColumnSpan($pictureBox, $image_index + 5)# 将表格布局面板添加到窗体$form.Controls.Add($tableLayoutPanel)# 显示窗体$form.ShowDialog() | Out-Null$form.Dispose()
希望这对你有帮助。
英文:
I am trying to have a dynamically created WinForm where I pass in a dictionary of names (keys) and the url where the image is hosted (values).
The code, loops through the dictionary and adds a button for each 'key' and when the button is pressed, it sets the picturebox to be the image at the url for that button.
There can be a different number of buttons each time (maybe up to 10).
I don't know if my approach (below) is the right one but I get most of what I want. The problem is that the image is only ever 'Mason' no matter which button is pressed.
Add-Type -AssemblyName System.Windows.Forms# Define a dictionary of names and image URLs$image_url_lookup = @{'Eric' = 'https://cdn.images.express.co.uk/img/dynamic/67/285x190/1758705_1.jpg''Mason' = 'https://cdn.images.express.co.uk/img/dynamic/67/285x190/1758732_1.jpg''Other' = 'https://cdn.images.express.co.uk/img/dynamic/67/285x190/1758699_1.jpg'}# Create a new form$form = New-Object System.Windows.Forms.Form$form.Text = "Select Images"$form.Width = 800$form.Height = 600$form.BackColor = [System.Drawing.Color]::White# Create a new table layout panel$tableLayoutPanel = New-Object System.Windows.Forms.TableLayoutPanel$tableLayoutPanel.Dock = [System.Windows.Forms.DockStyle]::Fill# Create a new picture box$pictureBox = New-Object System.Windows.Forms.PictureBox$pictureBox.Width = $form.Width - 100$pictureBox.Height = $form.Height - 100$pictureBox.Left = ($form.Width - $pictureBox.Width) / 2$pictureBox.Top = ($form.Height - $pictureBox.Height) / 2$pictureBox.BackColor = [System.Drawing.Color]::Transparent$pictureBox.SizeMode = [System.Windows.Forms.PictureBoxSizeMode]::Zoom$image_index = 0foreach ($name in $image_url_lookup.Keys) {$image_index++$button = New-Object System.Windows.Forms.Button$button.Name = "Button$image_index"$button.Text = $name$button.AccessibleName = $image_url_lookup[$name]$button.Add_Click({ $pictureBox.ImageLocation = $button.AccessibleName })$button.Width = 75$button.Height = 23# Add the button to the table layout panel$tableLayoutPanel.Controls.Add($button, $i, 0)}# Add the picture box to the table layout panel$tableLayoutPanel.Controls.Add($pictureBox, 0, 1)$tableLayoutPanel.SetColumnSpan($pictureBox, $image_index + 5)# Add the table layout panel to the form$form.Controls.Add($tableLayoutPanel)# Show the form$form.ShowDialog() | Out-Null$form.Dispose()
答案1
得分: 2
需要在循环中添加一个.GetNewClosure()调用，以便每个脚本块“记住”$button.AccessibleName在分配时的值，否则会发生的情况是，你总是获取到最后一个创建的$button的值：
foreach ($name in $image_url_lookup.Keys) {$image_index++$button = [System.Windows.Forms.Button]@{Name = "Button$image_index"Text = $nameAccessibleName = $image_url_lookup[$name]Width = 75Height = 23}$button.Add_Click({ $pictureBox.ImageLocation = $button.AccessibleName }.GetNewClosure())$tableLayoutPanel.Controls.Add($button, $i, 0)}
一个更好的方法是在事件中使用$this自动变量，这样就不需要新的闭包；这是由Theo在他的评论中提到的：
foreach ($name in $image_url_lookup.Keys) {$image_index++$button = [System.Windows.Forms.Button]@{Name = "Button$image_index"Text = $nameAccessibleName = $image_url_lookup[$name]Width = 75Height = 23}$button.Add_Click({ $pictureBox.ImageLocation = $this.AccessibleName })$tableLayoutPanel.Controls.Add($button, $i, 0)}
英文:
<!-- language-all: sh -->
You need to add a .GetNewClosure() call in your loop so that each scriptblock remembers what $button.AccessibleName was while it was assigned, otherwise what happens is that you're always getting the value of the last $button created:
foreach ($name in $image_url_lookup.Keys) {$image_index++$button = [System.Windows.Forms.Button]@{Name = "Button$image_index"Text = $nameAccessibleName = $image_url_lookup[$name]Width = 75Height = 23}$button.Add_Click({ $pictureBox.ImageLocation = $button.AccessibleName }.GetNewClosure())$tableLayoutPanel.Controls.Add($button, $i, 0)}
A much better approach would be to use the $this automatic variable in your events, that way there is no need for a new closure; this was hinted at by Theo in his comment:
foreach ($name in $image_url_lookup.Keys) {$image_index++$button = [System.Windows.Forms.Button]@{Name = "Button$image_index"Text = $nameAccessibleName = $image_url_lookup[$name]Width = 75Height = 23}$button.Add_Click({ $pictureBox.ImageLocation = $this.AccessibleName })$tableLayoutPanel.Controls.Add($button, $i, 0)}
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