1 files changed, 28 insertions, 7 deletions
diff --git a/src/mscorlib/src/System/StringComparer.cs b/src/mscorlib/src/System/StringComparer.cs
index 57bdf4c6b2..02e8d71d0e 100644
--- a/src/mscorlib/src/System/StringComparer.cs
+++ b/src/mscorlib/src/System/StringComparer.cs
@@ -62,9 +62,31 @@ namespace System {
             }
         }
 
+        // Convert a StringComparison to a StringComparer
+        public static StringComparer FromComparison(StringComparison comparisonType)
+        {
+            switch (comparisonType)
+            {
+                case StringComparison.CurrentCulture:
+                    return CurrentCulture;
+                case StringComparison.CurrentCultureIgnoreCase:
+                    return CurrentCultureIgnoreCase;
+                case StringComparison.InvariantCulture:
+                    return InvariantCulture;
+                case StringComparison.InvariantCultureIgnoreCase:
+                    return InvariantCultureIgnoreCase;
+                case StringComparison.Ordinal:
+                    return Ordinal;
+                case StringComparison.OrdinalIgnoreCase:
+                    return OrdinalIgnoreCase;
+                default:
+                    throw new ArgumentException(Environment.GetResourceString("NotSupported_StringComparison"), nameof(comparisonType));
+            }
+        }
+
         public static StringComparer Create(CultureInfo culture, bool ignoreCase) {
             if( culture == null) {
-                throw new ArgumentNullException("culture");
+                throw new ArgumentNullException(nameof(culture));
             }
             Contract.Ensures(Contract.Result<StringComparer>() != null);
             Contract.EndContractBlock();
@@ -110,7 +132,7 @@ namespace System {
         
         public int GetHashCode(object obj) {
             if( obj == null) {
-                throw new ArgumentNullException("obj");
+                throw new ArgumentNullException(nameof(obj));
             }
             Contract.EndContractBlock();
 
@@ -161,7 +183,7 @@ namespace System {
                 
         public override int GetHashCode(string obj) {
             if( obj == null) {
-                throw new ArgumentNullException("obj");
+                throw new ArgumentNullException(nameof(obj));
             }
             Contract.EndContractBlock();
 
@@ -229,7 +251,7 @@ namespace System {
                 
         public override int GetHashCode(string obj) {
             if( obj == null) {
-                throw new ArgumentNullException("obj");
+                throw new ArgumentNullException(nameof(obj));
             }
             Contract.EndContractBlock();
 
@@ -311,7 +333,7 @@ namespace System {
                 
         public override int GetHashCode(string obj) {
             if( obj == null) {
-                throw new ArgumentNullException("obj");
+                throw new ArgumentNullException(nameof(obj));
             }
             Contract.EndContractBlock();
 
@@ -385,10 +407,9 @@ namespace System {
             return x.Equals(y);
         }               
 
-        [System.Security.SecuritySafeCritical]            
         public override int GetHashCode(string obj) {
             if( obj == null) {
-                throw new ArgumentNullException("obj");
+                throw new ArgumentNullException(nameof(obj));
             }
             Contract.EndContractBlock();