Prefer use of interpolated strings in PresentationCore

[halgab]

Follow-up to #8519

Description

We replace as many manual string concatenations and string.Format with interpolated strings. This saves allocations in many instances, and makes for a more readable code.

Customer Impact

Less allocations

Regression

No

Testing

CI

Risk

Low. Most changes are automated using the IDE

Microsoft Reviewers: Open in CodeFlow

[rchauhan18]

@halgab A DRT(test) is failing on this PR: DrtColorAPI
You can find this test on our public repo: https://github.com/dotnet/wpf-test

I think so the test is failing due to some missing elements in this file after change.

[halgab]

After having another read, the difference between the current version and mine is that when nativeColorValue is empty, the current version still appends a separator value, which is not the case with my version. I feel like my version is more correct.
Tell me if you prefer that I maintain the current behaviour.

[ThomasGoulet73]

Your changes are functionally different. Floats were formatted using format previously but are now always formatted using R. Also, the loop in your changes always prepends the separator instead of prepending the separator only when between items: ",A,B,C" vs "A,B,C". Also, there should be a space here between {uriString} and {scRgbColor.a:R}, it was there before your changes.

I would recommend testing your changes because by looking at the code I don't see how your changes returns the same result as the existing code.

[halgab]

Those are valid points. I'll rollback the functional changes. I'd like to keep the constant format though, as format is always set to R before this loop, and that's what makes it possible to use interpolated strings. What do you think?

[dipeshmsft]

@halgab IMO, this change makes it a bit harder to understand what's happening here. Maybe we can use string.Format here ?

[h3xds1nz]

@dipeshmsft We can just use regular interpolation and space it out, like this:

return $"{Int32.Parse("1")}," +
       $"{Int32.Parse("1")}";

It will produce the following:

DefaultInterpolatedStringHandler defaultInterpolatedStringHandler = new DefaultInterpolatedStringHandler(1, 2);
defaultInterpolatedStringHandler.AppendFormatted<int>(int.Parse("1"));
defaultInterpolatedStringHandler.AppendLiteral(",");
defaultInterpolatedStringHandler.AppendFormatted<int>(int.Parse("1"));
defaultInterpolatedStringHandler.ToStringAndClear();

So the change like this:

return $"{{{StrokeFIndices.GetStringRepresentation(_hitSegment.BeginFIndex)}," +
         $"{StrokeFIndices.GetStringRepresentation(_inSegment.BeginFIndex)}," +
         $"{StrokeFIndices.GetStringRepresentation(_inSegment.EndFIndex)}," +
         $"{StrokeFIndices.GetStringRepresentation(_hitSegment.EndFIndex)}}}";

[dipeshmsft]

@h3xds1nz, I was just going through DefaultInterpolatedStringHandler in your PR and your suggestion sounds good.

[dipeshmsft]

Again, this seems hard to be understood. Maybe consider using string.Concat / string.Format here.

[h3xds1nz]

Same here, we can just use regular string interpolation and space it out over multiple lines, no need for string.Format ugliness.

[dipeshmsft]

Rather than this, it would be better to keep using format here. Although, I don't think we are going to change static format, this keeps using format and keeps it maintainable.

Suggested change

	sb.Append(provider, $"{nativeColorValue[i]:R}");
	sb.AppendFormat(provider, $"{{0:{format}}}", nativeColorValue[i]);

[dipeshmsft]

We can split this back in two lines and use the same suggestion as below for the second line.

[dipeshmsft]

@halgab, can you take a look at the above PR and make the necessary changes ?