using System;
using System.Linq.Expressions;
namespace Sample
{
class Program
{
private static void DisplayTree(int indent, string message, Expression expression)
{
string output = String.Format("{0} {1} ! NodeType: {2}; Expr: {3} ",
"".PadLeft(indent, '>'), message, expression.NodeType, expression);
indent++;
switch (expression.NodeType)
{
case ExpressionType.Lambda:
Console.WriteLine(output);
LambdaExpression lambdaExpr = (LambdaExpression)expression;
foreach (var parameter in lambdaExpr.Parameters)
{
DisplayTree(indent, "Parameter", parameter);
}
DisplayTree(indent, "Body", lambdaExpr.Body);
break;
case ExpressionType.Constant:
ConstantExpression constExpr = (ConstantExpression)expression;
Console.WriteLine("{0} Const Value: {1}", output, constExpr.Value);
break;
case ExpressionType.Parameter:
ParameterExpression paramExpr = (ParameterExpression)expression;
Console.WriteLine("{0} Param Type: {1}", output, paramExpr.Type.Name);
break;
case ExpressionType.Equal:
case ExpressionType.AndAlso:
case ExpressionType.GreaterThan:
BinaryExpression binExpr = (BinaryExpression)expression;
if (binExpr.Method != null)
{
Console.WriteLine("{0} Method: {1}", output, binExpr.Method.Name);
}
else
{
Console.WriteLine(output);
}
DisplayTree(indent, "Left", binExpr.Left);
DisplayTree(indent, "Right", binExpr.Right);
break;
case ExpressionType.MemberAccess:
MemberExpression memberExpr = (MemberExpression)expression;
Console.WriteLine("{0} Member Name: {1}, Type: {2}", output,
memberExpr.Member.Name, memberExpr.Type.Name);
DisplayTree(indent, "Member Expr", memberExpr.Expression);
break;
default:
Console.WriteLine();
Console.WriteLine("{0} {1}", expression.NodeType, expression.Type.Name);
break;
}
}
static void Main()
{
Expression> expression = r => r.Country == "UK" && r.Wins > 6;
DisplayTree(0, "Lambda", expression);
}
}
}