diff --git a/src/Api/VSCodeApi.ts b/src/Api/VSCodeApi.ts
index 42636bf..233e949 100644
--- a/src/Api/VSCodeApi.ts
+++ b/src/Api/VSCodeApi.ts
@@ -153,4 +153,19 @@ export class VSCodeApi {
         return null;
     }
 
+    public ReadNextLineFromCurrent(): string {
+        const lineCount: number = this.GetLineCount();
+        const curLine: number = this.GetActiveLine();
+
+        for (let i: number = curLine; i < lineCount - 1; i++) {
+
+            // Skip empty line
+            const line: string = this.ReadLine(i + 1);
+            if (StringUtil.IsNullOrWhiteSpace(line)) continue;
+
+            return line;
+        }
+
+        return null;
+    }
 }
diff --git a/src/Domain/Lang/DocommentDomainCSharp.ts b/src/Domain/Lang/DocommentDomainCSharp.ts
index d9a1ec2..6142c1a 100644
--- a/src/Domain/Lang/DocommentDomainCSharp.ts
+++ b/src/Domain/Lang/DocommentDomainCSharp.ts
@@ -36,27 +36,16 @@ export class DocommentDomainCSharp extends DocommentDomain {
         // NG: Line is NOT /// (NG: ////)
         const activeLine: string = this._vsCodeApi.ReadLineAtCurrent();
         if (activeLine == null) return false;
-        if (isSlashKey) {
-            const isDocComment: boolean = SyntacticAnalysisCSharp.IsDocCommentStrict(activeLine);
-            if (!isDocComment) return false;
-
-            // NG: '/' => Insert => Event => ' /// '
-            if (SyntacticAnalysisCSharp.IsDoubleDocComment(activeLine)) return false;
-        }
-        if (this._isEnterKey) {
+        if (isSlashKey || this._isEnterKey) {
             const isDocComment: boolean = SyntacticAnalysisCSharp.IsDocComment(activeLine);
             if (!isDocComment) return false;
-        }
 
-        // NG: Position is NOT ///
-        // const position: number = this._vsCodeApi.GetActiveCharPosition();
-        // const positionDocComment: number = activeLine.lastIndexOf('///') + ((isEnterKey) ? 3 : 2);
-        // const isLastPosition: boolean = (position === positionDocComment);
-        // if (!isLastPosition) return false;
+            const previousLine: string = this._vsCodeApi.ReadPreviousLineFromCurrent();
+            if (SyntacticAnalysisCSharp.IsDocComment(previousLine)) return false;
 
-        // NG: Previous line is XML document comment
-        // const previousLine: string = this._vsCodeApi.ReadPreviousLineFromCurrent();
-        // if (SyntacticAnalysisCSharp.IsDocComment(previousLine)) return false;
+            const nextLine: string = this._vsCodeApi.ReadNextLineFromCurrent();
+            if (SyntacticAnalysisCSharp.IsDocComment(nextLine)) return false;
+        }
 
         // OK
         return true;
@@ -86,7 +75,7 @@ export class DocommentDomainCSharp extends DocommentDomain {
 
 
         /*-------------------------------------------------------------------------
-         * 
+         *
          *-----------------------------------------------------------------------*/
         const isInMethod = false; // fixme:
         if (isInMethod) return CodeType.None;
diff --git a/src/SyntacticAnalysis/SyntacticAnalysisCSharp.ts b/src/SyntacticAnalysis/SyntacticAnalysisCSharp.ts
index 27cccf4..8ca9b6c 100644
--- a/src/SyntacticAnalysis/SyntacticAnalysisCSharp.ts
+++ b/src/SyntacticAnalysis/SyntacticAnalysisCSharp.ts
@@ -17,16 +17,8 @@ export class SyntacticAnalysisCSharp {
         return (activeChar === '/');
     }
 
-    public static IsDocCommentStrict(activeLine: string): boolean {
-        return activeLine.match(/(?:[^/]\/{3}[ \t]*$)|(?:^\/{3}[^/])|(?:^\/{3}[ \t]*$)/) !== null; // fixme: to simple
-    }
-
     public static IsDocComment(activeLine: string): boolean {
-        return activeLine.match(/\/{3}/) !== null;
-    }
-
-    public static IsDoubleDocComment(activeLine: string): boolean {
-        return activeLine.match(/^[ \t]+\/{3} $/) !== null;
+        return activeLine.match(/^\s*?\/{3}\s*$/) !== null;
     }
 
     /*-------------------------------------------------------------------------
@@ -97,7 +89,7 @@ export class SyntacticAnalysisCSharp {
         let paramName: Array<string> = new Array<string>();
         params[1].split(',').forEach(param => {
             const hasOptionaParam: boolean = param.match(/\S+\s+\S+\s*=/) !== null;
-            const name: RegExpMatchArray = (hasOptionaParam) 
+            const name: RegExpMatchArray = (hasOptionaParam)
                                            ? param.match(/\S+\s+(\S+)\s*=.*/)
                                            : param.match(/(\S+)\s*$/);
             if (name !== null && name.length === 2) {
diff --git a/test/SyntacticAnalysis/SyntacticAnalysisCSharp.test.ts b/test/SyntacticAnalysis/SyntacticAnalysisCSharp.test.ts
index c7ff022..c9990ae 100644
--- a/test/SyntacticAnalysis/SyntacticAnalysisCSharp.test.ts
+++ b/test/SyntacticAnalysis/SyntacticAnalysisCSharp.test.ts
@@ -208,4 +208,24 @@ suite('SyntacticAnalysis.SyntacticAnalysisCSharp.IsClass Tests', () => {
             assert.equal(actual[1], 'onComplete');
         });
 
+    test(`
+        Category: Black-box testing
+        Class   : SyntacticAnalysis.SyntacticAnalysisCSharp
+        Method  : IsDocComment
+    `, () => {
+            assert.equal(SyntacticAnalysisCSharp.IsDocComment('///'), true, '///');
+            assert.equal(SyntacticAnalysisCSharp.IsDocComment(' ///'), true, ' ///');
+            assert.equal(SyntacticAnalysisCSharp.IsDocComment(' /// '), true, ' /// ');
+
+            assert.equal(SyntacticAnalysisCSharp.IsDocComment('/// ///'), false, '/// ///');
+            assert.equal(SyntacticAnalysisCSharp.IsDocComment(' /// ///'), false, ' /// ///');
+            assert.equal(SyntacticAnalysisCSharp.IsDocComment('//////'), false, '//////');
+            assert.equal(SyntacticAnalysisCSharp.IsDocComment(' //////'), false, ' //////');
+            assert.equal(SyntacticAnalysisCSharp.IsDocComment(' /////'), false, ' /////');
+            assert.equal(SyntacticAnalysisCSharp.IsDocComment(' /// //'), false, ' /// //');
+            assert.equal(SyntacticAnalysisCSharp.IsDocComment(' //// ///'), false, ' //// ///');
+            assert.equal(SyntacticAnalysisCSharp.IsDocComment(' /// <bla>'), false, "' /// <bla>'");
+        });
+
+
 });