Update snippets per issue. (#37793)

* Update snippets per issue.

* Add project file.

* Troubleshoot snippet build error.

* Troubleshoot snippet error.

samples/snippets/csharp/VS_Snippets_CLR_System/system.IO.StreamReader/CS/compose.csproj

@@ -0,0 +1,11 @@
+<Project Sdk="Microsoft.NET.Sdk">
+
+ <PropertyGroup>
+ <OutputType>Exe</OutputType>
+ <TargetFramework>net6.0</TargetFramework>
+ <Nullable>enable</Nullable>
+ <ImplicitUsings>enable</ImplicitUsings>
+ <StartupObject>CompBuf</StartupObject>
+ </PropertyGroup>
+
+</Project>

samples/snippets/csharp/VS_Snippets_CLR_System/system.IO.StreamReader/CS/source2.cs

@@ -13,11 +13,8 @@ public static void Main()
  Console.WriteLine($"{FILE_NAME} does not exist!");
  return;
  }
- FileStream fsIn = new FileStream(FILE_NAME, FileMode.Open,
- FileAccess.Read, FileShare.Read);
- // Create an instance of StreamReader that can read
- // characters from the FileStream.
- using (StreamReader sr = new StreamReader(fsIn))
+ // Create an instance of StreamReader characters from the file.
+ using (StreamReader sr = new StreamReader(FILE_NAME))
  {
  string input;
  // While not at the end of the file, read lines from the file.

samples/snippets/csharp/VS_Snippets_CLR_System/system.IO.StreamReader/CS/source3.cs

@@ -13,18 +13,19 @@ public static void Main()
  Console.WriteLine($"{FILE_NAME} does not exist.");
  return;
  }
- FileStream f = new FileStream(FILE_NAME, FileMode.Open,
- FileAccess.Read, FileShare.Read);
- // Create an instance of BinaryReader that can
- // read bytes from the FileStream.
- using (BinaryReader br = new BinaryReader(f))
+ using (FileStream f = new FileStream(FILE_NAME, FileMode.Open, FileAccess.Read, FileShare.Read))
  {
- byte input;
- // While not at the end of the file, read lines from the file.
- while (br.PeekChar() > -1 )
+ // Create an instance of BinaryReader that can
+ // read bytes from the FileStream.
+ using (BinaryReader br = new BinaryReader(f))
  {
- input = br.ReadByte();
- Console.WriteLine(input);
+ byte input;
+ // While not at the end of the file, read lines from the file.
+ while (br.PeekChar() > -1)
+ {
+ input = br.ReadByte();
+ Console.WriteLine(input);
+ }
  }
  }
  }