format symbol $" in PowerShell For C# code

Question

I am trying to convert the C# code of the link below to PowerShell code, and I can't process the C# symbol【 $" 】 in PowerShell.

https://github.com/dlemstra/Magick.NET/blob/master/docs/Drawing.md

All related files: https://www.upload.ee/files/12630601/File.zip.html

Console prompt error:

ERROR: Exception calling "Format" with "1" argument(s): "Input string was not in a correct format."
Adding Text To Existing Image.ps1 (15, 1): ERROR: At Line: 15 char: 1
ERROR: + $caption = New-Object ImageMagick.MagickImage([string]::format("capti ...
ERROR: + ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
ERROR:     + CategoryInfo          : NotSpecified: (:) [], MethodInvocationException
ERROR:     + FullyQualifiedErrorId : FormatException
ERROR:

Buggy code line for PS:

$caption = New-Object ImageMagick.MagickImage([string]::format("$caption:{$textToWrite}"), $readSettings)

Source code line for C#:

using (var caption = new MagickImage($"caption:{textToWrite}", readSettings))

Powershell Code:

Add-Type -Path ".\Magick.NET-Q16-AnyCPU.dll"

$image = New-Object ImageMagick.MagickImage logo.png
$pathToBackgroundImage = "bg.jpg";
$pathToNewImage = "img_ok.png";
$textToWrite = "Insert This Text Into Image";
$readSettings = New-Object -TypeName ImageMagick.MagickReadSettings
$readSettings.Font = "Calibri"
$readSettings.TextGravity = "Center"
$readSettings.BackgroundColor = New-Object ImageMagick.MagickColor("Transparent")
$readSettings.Height = 250
$readSettings.Width = 680

$image = New-Object ImageMagick.MagickImage($pathToBackgroundImage)
$caption = New-Object ImageMagick.MagickImage([string]::format("caption:{$textToWrite}"), $readSettings)

$image.Composite($caption, 590, 450, [ImageMagick.CompositeOperator]::Over)
$image.Write($pathToNewImage)
$image.Dispose()

C# source code:

var pathToBackgroundImage = "path/to/background.png";
var pathToNewImage = "path/to/newImage.png";
var textToWrite = "Insert This Text Into Image";

// These settings will create a new caption
// which automatically resizes the text to best
// fit within the box.

var readSettings = new MagickReadSettings
{
    Font = "Calibri",
    TextGravity = Gravity.Center,
    BackgroundColor = MagickColors.Transparent,
    Height = 250, // height of text box
    Width = 680 // width of text box
};

using (var image = new MagickImage(pathToBackgroundImage))
{
    using (var caption = new MagickImage($"caption:{textToWrite}", readSettings))
    {
        // Add the caption layer on top of the background image
        // at position 590,450
        image.Composite(caption, 590, 450, CompositeOperator.Over);

        image.Write(pathToNewImage);
    }
}

$caption = New-Object ImageMagick.MagickImage([string]::format("$caption:{$textToWrite}"), $readSettings) you are trying to define a variable...but in the constructor reference that same variable...that doesnt make sense...the C# code the caption string is not interpolated...its just a string...equivalent code would instead be just "caption:{$textToWrite}" — Ctznkane525
– Ctznkane525, Commented Dec 12, 2020 at 1:26
This line of C # code is turned into a PS script, a bit difficult, multiple attempts are not successful — tianyi
– tianyi, Commented Dec 12, 2020 at 2:26

mklement0 · Accepted Answer · 2020-12-12 02:46:24Z

3

The problem you're seeing in the error is that you are using a Powershell interpolated string. It thinks you are injecting the variable "$caption" into the string.

This is because in Powershell, strings that are enclosed in double quotes " are treated as interpolated strings. Where as strings enclosed in single quotes ' are treated as literal strings.

In C#, all strings are enclosed in double quotes. But if you want to use interpolated strings, then you preface it with a $ sign, and then you inject your code by using {curly brackets}.

Powershell Example:

$name = "Chad"
Write-Host "Hello $name!" // Interpolated
Write-Host 'Hello $name!' // Literal

Powershell sees the double quotes, and knows to look for variable names inside of the string. In this case, it sees $name and swaps it out with its value. But when single quotes are used, it outputs the literal string.

C# example:

var name = "chad";
Console.WriteLine($"Hello {name}!"); // Interpolated
Console.WriteLine("Hello {name}!");  // Literal

Whereas in C#, this is how interpolated and literal strings work...

So you need to convert the C# interpolated string into a PowerShell interpolated string:

From (C#):

$"caption:{textToWrite}"

To (PowerShell):

"caption:$textToWrite"

edited Dec 12, 2020 at 2:46

mklement0

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answered Dec 12, 2020 at 1:32

Chad Baldwin

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2 Comments

tianyi Over a year ago

The problem has been resolved,thanks$caption = New-Object ImageMagick.MagickImage([string]::format("caption:$textToWrite"), $readSettings)

tianyi Over a year ago

Do you have a good perspective? about using and new stackoverflow.com/questions/65261346/…

Esperento57 · Accepted Answer · 2020-12-12 05:13:03Z

1

You can do it :

 $Arg1="caption:{0}" -f $textToWrite
 $caption = New-Object ImageMagick.MagickImage($Arg1, $readSettings)

answered Dec 12, 2020 at 5:13

Esperento57

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1 Comment

tianyi Over a year ago

also successfully execute, the same effects above,Do you have a good perspective? about using and new, stackoverflow.com/questions/65261346/…

Ctznkane525 · Accepted Answer · 2020-12-12 02:31:33Z

0

$caption = New-Object ImageMagick.MagickImage([string]::format("$caption:{$textToWrite}"), $readSettings)

you are trying to define a variable...but in the constructor reference that same variable ($caption)that doesnt make sense

the C# code the caption string is not interpolated...its just a string...equivalent code would instead be just "caption:$textToWrite"

 $caption = New-Object ImageMagick.MagickImage([string]::format("caption:$textToWrite"), $readSettings)

edited Dec 12, 2020 at 2:31

answered Dec 12, 2020 at 1:29

Ctznkane525

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2 Comments

tianyi Over a year ago

ERROR: Exception calling "Format" with "1" argument(s): "Input string was not in a correct format."

tianyi Over a year ago

In the problem description, all related files have just been uploaded, wow,This line of code is converted into PS, quite difficult

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