System.Xml: String.Compare -> String.Equals

Per the Best Practices for Using Strings at
http://msdn.microsoft.com/en-us/library/dd465121(v=vs.110).aspx

* Use an overload of the String.Equals method to test whether two
strings are equal.
* Use the String.Compare and String.CompareTo methods to sort strings,
not to check for equality.

Author: justinvp

src/System.Xml.ReaderWriter/src/System/Xml/Core/XmlTextReaderImpl.cs

@@ -2300,22 +2300,22 @@ private Encoding CheckEncoding(string newEncodingName)
                 return _ps.encoding;
             }
 
-            if (0 == String.Compare(newEncodingName, "ucs-2", StringComparison.OrdinalIgnoreCase) ||
-                0 == String.Compare(newEncodingName, "utf-16", StringComparison.OrdinalIgnoreCase) ||
-                0 == String.Compare(newEncodingName, "iso-10646-ucs-2", StringComparison.OrdinalIgnoreCase) ||
-                0 == String.Compare(newEncodingName, "ucs-4", StringComparison.OrdinalIgnoreCase))
+            if (String.Equals(newEncodingName, "ucs-2", StringComparison.OrdinalIgnoreCase) ||
+                String.Equals(newEncodingName, "utf-16", StringComparison.OrdinalIgnoreCase) ||
+                String.Equals(newEncodingName, "iso-10646-ucs-2", StringComparison.OrdinalIgnoreCase) ||
+                String.Equals(newEncodingName, "ucs-4", StringComparison.OrdinalIgnoreCase))
             {
                 if (_ps.encoding.WebName != "utf-16BE" &&
                      _ps.encoding.WebName != "utf-16" &&
-                     0 != String.Compare(newEncodingName, "ucs-4", StringComparison.OrdinalIgnoreCase))
+                     !String.Equals(newEncodingName, "ucs-4", StringComparison.OrdinalIgnoreCase))
                 {
                     ThrowWithoutLineInfo(SR.Xml_MissingByteOrderMark);
                 }
                 return _ps.encoding;
             }
 
             Encoding newEncoding = null;
-            if (0 == String.Compare(newEncodingName, "utf-8", StringComparison.OrdinalIgnoreCase))
+            if (String.Equals(newEncodingName, "utf-8", StringComparison.OrdinalIgnoreCase))
             {
                 newEncoding = new UTF8Encoding(true, true);
             }
@@ -5030,7 +5030,7 @@ private bool ParsePI(BufferBuilder piInDtdStringBuilder)
             int nameEndPos = ParseName();
             string target = _nameTable.Add(_ps.chars, _ps.charPos, nameEndPos - _ps.charPos);
 
-            if (string.Compare(target, "xml", StringComparison.OrdinalIgnoreCase) == 0)
+            if (string.Equals(target, "xml", StringComparison.OrdinalIgnoreCase))
             {
                 Throw(target.Equals("xml") ? SR.Xml_XmlDeclNotFirst : SR.Xml_InvalidPIName, target);
             }

src/System.Xml.ReaderWriter/src/System/Xml/Core/XmlTextReaderImplAsync.cs

@@ -3646,7 +3646,7 @@ private async Task<bool> ParsePIAsync(BufferBuilder piInDtdStringBuilder)
             int nameEndPos = await ParseNameAsync().ConfigureAwait(false);
             string target = _nameTable.Add(_ps.chars, _ps.charPos, nameEndPos - _ps.charPos);
 
-            if (string.Compare(target, "xml", StringComparison.OrdinalIgnoreCase) == 0)
+            if (string.Equals(target, "xml", StringComparison.OrdinalIgnoreCase))
             {
                 Throw(target.Equals("xml") ? SR.Xml_XmlDeclNotFirst : SR.Xml_InvalidPIName, target);
             }

src/System.Xml.ReaderWriter/src/System/Xml/Core/XmlTextReaderImplHelpers.cs

@@ -726,7 +726,7 @@ public int Compare(object x, object y)
                     }
                 }
 
-                // string.Compare does reference euqality first for us, so we don't have to do it here
+                // string.Compare does reference equality first for us, so we don't have to do it here
                 int result = string.Compare(localName, localName2, StringComparison.Ordinal);
                 if (result != 0)
                 {

src/System.Xml.ReaderWriter/src/System/Xml/Core/XmlWellformedWriter.cs

@@ -954,7 +954,7 @@ public override void WriteProcessingInstruction(string name, string text)
                 }
 
                 // xml declaration is a special case (not a processing instruction, but we allow WriteProcessingInstruction as a convenience)
-                if (name.Length == 3 && string.Compare(name, "xml", StringComparison.OrdinalIgnoreCase) == 0)
+                if (name.Length == 3 && string.Equals(name, "xml", StringComparison.OrdinalIgnoreCase))
                 {
                     if (_currentState != State.Start)
                     {

src/System.Xml.ReaderWriter/src/System/Xml/Core/XmlWellformedWriterAsync.cs

@@ -817,7 +817,7 @@ public override async Task WriteProcessingInstructionAsync(string name, string t
                 }
 
                 // xml declaration is a special case (not a processing instruction, but we allow WriteProcessingInstruction as a convenience)
-                if (name.Length == 3 && string.Compare(name, "xml", StringComparison.OrdinalIgnoreCase) == 0)
+                if (name.Length == 3 && string.Equals(name, "xml", StringComparison.OrdinalIgnoreCase))
                 {
                     if (_currentState != State.Start)
                     {