Zircon The latest code HelpDialog.cs compilation resulted Compiler Error CS0131

[test39857]

The latest code HelpDialog.cs compilation resulted Compiler Error CS0131. HelpDialog.cs code as below:

public void OnSelectedChanged(HelpContainer oValue, HelpContainer nValue)
{
oValue?.Visible = false;

SelectedChanged?.Invoke(this, EventArgs.Empty);

nValue?.Update();

nValue?.Visible = true;
}

Compiler Error CS0131:The left-hand side of an assignment must be a variable, property or indexer

I checked the grammar and there are no errors, but I don't know why this error keeps occurring.

However, the equivalent code shown below compiles successfully. Could someone please explain this discrepancy?

public void OnSelectedChanged(HelpContainer oValue, HelpContainer nValue)
{
//oValue?.Visible = false;
if (oValue != null)
{
oValue.Visible = false;
}

SelectedChanged?.Invoke(this, EventArgs.Empty);

nValue?.Update();

//nValue?.Visible = true;
if (nValue != null)
{
nValue.Visible = true;
}

}

 

[Shyfx]

doesnt need a nullable ? on the ovalue or check the value for null first like in the one that works

you can add a ? onto HelpContainer? oValue if you want the ovalue? to work

 

[Far]

sounds like you might not have the latest c# versions installed to know about nullable properties.

The current code works fine on latest visual studio

 

[test39857]

sounds like you might not have the latest c# versions installed to know about nullable properties.

The current code works fine on latest visual studio

You're right. I haven't upgraded latest c# versions.

 

[test39857]

sounds like you might not have the latest c# versions installed to know about nullable properties.

The current code works fine on latest visual studio

I am still getting errors CS0131 after updating to the latest version of VS2022 17.14.25.
Which version of Visual Studio supports this feature?

 

[Far]

2022 is fine, but make sure you have the latest c# and .net versions installed

 

[test39857]

2022 is fine, but make sure you have the latest c# and .net versions installed

I installed the VS2022 Community Edition.It has been updated to the latest version.
Error CS0131 will occur by default; it will only work without error if `<LangVersion>preview</LangVersion>` is manually configured in the project file.

Could you tell me which version of VS2022 to install and how to configure it?

 

[Far]

If you have .net 8 + installed in visual studio it should include the correct c# versions

 

[test39857]

If you have .net 8 + installed in visual studio it should include the correct c# versions

.NET 8 and .NET 9 are installed.
Why am I getting this error message?
I'll try again.

 

[Far]

You'll need to google it. If you're installed those extensions in visual studio it should compile fine.