using System;
using System.Linq.Expressions;
using System.Linq;
using System.Collections.Generic;
namespace Sample
{
public class MainEntryPoint
{
static int Main(string[] args)
{
Expression<Func<Racer, bool>> expression = r => r.Country == "UK" && r.Wins > 6;
DisplayTree(0, "lambda", expression);
return 0;
}
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, "Paramter", parameter);
}
DisplayTree(indent, "Body", lambdaExpr.Body);
break;
case ExpressionType.Parameter:
ParameterExpression parameterExpr = (ParameterExpression)expression;
Console.WriteLine("{0} Parameter Type:{1}", output, parameterExpr.Type.Name);
break;
case ExpressionType.Constant:
ConstantExpression constExpr = (ConstantExpression)expression;
Console.WriteLine("{0} Constant Value:{1}", output, constExpr.Value);
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;
}
}
}
[Serializable]
public class Racer : IComparable<Racer>, IFormattable
{
public string FirstName { get; set;}
public string LastName { get; set;}
public int Wins { get; set;}
public string Country { get; set;}
public int Starts { get; set;}
public IEnumerable<string> Cars { get; private set;}
public IEnumerable<int> Years { get; private set;}
public Racer(string firstName, string lastName, int wins, string country, int starts, IEnumerable<string> cars,IEnumerable<int> years)
{
this.FirstName = firstName;
this.LastName = lastName;
this.Wins = wins;
this.Country = country;
this.Starts = starts;
this.Cars = new List<string>(cars);
this.Years =new List<int>(years);
}
public Racer(string firstName, string lastName, int wins, string country, int starts): this(firstName, lastName, wins, country, starts, null, null)
{
}
public override string ToString()
{
return string.Format("{0} {1}", FirstName, LastName);
}
public int CompareTo(Racer other)
{
if(other == null)
return -1;
return string.Compare(this.LastName, other.LastName);
}
public string ToString(string format)
{
return ToString(format, null);
}
public string ToString(string format, IFormatProvider formatProvider)
{
switch(format)
{
case null:
case "N":
return ToString();
case "F":
return FirstName;
case "L":
return LastName;
case "C":
return Country;
case "S":
return Starts.ToString();
case "W":
return Wins.ToString();
case "A":
return string.Format("{0} {1}, {2}, starts: {3}, wins: {4}", FirstName, LastName, Country, Starts, Wins);
default:
throw new FormatException(string.Format("Format {0} not supported", format));
}
}
}
}
转载请注明原文地址: https://ju.6miu.com/read-12116.html
