protected override Expression VisitMethodCall(MethodCallExpression node)
{
if (node == null)
{
throw new ArgumentNullException(nameof(node));
}
if (node.Object != null &&
node.Object.NodeType == ExpressionType.MemberAccess &&
((MemberExpression)node.Object).RootExpressionType() == ExpressionType.Parameter)
{
string format;
if (node.Method.Name == "StartsWith" ||
node.Method.Name == "Contains" ||
node.Method.Name == "EndsWith")
{
format = "({0} LIKE {1})";
}
else if (node.Method.Name == "IgnoreExpression")
{
return(node);
}
else
{
throw new NotSupportedException($"不受支持的方法调用 {node.Method.Name}");
}
// 解析的时候需要在其他方法内根据方法名拼接字符串，
// 所以在这里需要一个全局变量保存方法名
_tempMethod = node.Method.Name;
Visit(node.Object);
Visit(node.Arguments[0]);
var right = _stringStack.Pop();
var left = _stringStack.Pop();
_stringStack.Push(string.Format(format, left, right));
}
else if (node.Method.Name == "DefaultTrue")
{
_stringStack.Push("1=1");
}
else if (node.Method.Name == "DefaultFalse")
{
_stringStack.Push("1=0");
}
else
{
var obj = ResolveValue(node.GetValue());
var parameterName = $"{_prefix}__p_{_parameterIndex++}";
_parameters.Add(new KeyValuePair <string, object>(parameterName, obj));
_stringStack.Push($" {parameterName} ");
}
return(node);
}
protected override Expression VisitMethodCall(MethodCallExpression node)
{
if (node.InvolvesParameter())
{
HandleParameter(node);
}
else
{
_sb.Append("@" + Parameters.CurrentIndex);
Parameters.RegisterParameter(node.GetValue());
}
return(node);
}
private string ResolveCallClause(MethodCallExpression node)
{
var obj = node.Object;
if (obj != null && obj.NodeType == ExpressionType.MemberAccess)
{
var expression = (MemberExpression)obj;
var rootNodeType = expression.GetRootType(out var stack);
if (rootNodeType == ExpressionType.Parameter)
{
return(ResolveParameterMemberMethodCall(node, stack));
}
}
var value = (bool)node.GetValue();
return(value ? "1=1" : "1<>1");
}
/// <summary>
/// Get the value from an expression.
/// </summary>
/// <param name="expression">The expression to be evaluated.</param>
/// <returns>the value.</returns>
public static object GetValue(this Expression expression, JsonSerializerSettings jsonSerializerSettings)
{
if (expression == null)
{
throw new ArgumentNullException(nameof(expression));
}
switch (expression.NodeType)
{
case ExpressionType.Constant:
{
ConstantExpression constantExpression = expression as ConstantExpression;
if (constantExpression == null)
{
throw new ArgumentException($"Expected {nameof(expression)} to be of type {nameof(ConstantExpression)}\r\n\t{expression}", nameof(expression));
}
return(constantExpression.GetValue());
}
case ExpressionType.Call:
{
MethodCallExpression methodCallExpression = expression as MethodCallExpression;
if (methodCallExpression == null)
{
throw new ArgumentException($"Expected {nameof(expression)} to be of type {nameof(MethodCallExpression)}\r\n\t{expression}", nameof(expression));
}
return(methodCallExpression.GetValue(jsonSerializerSettings));
}
case ExpressionType.Convert:
{
UnaryExpression unaryExpression = expression as UnaryExpression;
if (unaryExpression == null)
{
throw new ArgumentException($"Expected {nameof(expression)} to be of type {nameof(UnaryExpression)}\r\n\t{expression}", nameof(expression));
}
return(unaryExpression.GetValue(jsonSerializerSettings));
}
case ExpressionType.MemberAccess:
{
MemberExpression memberExpression = expression as MemberExpression;
if (memberExpression == null)
{
throw new ArgumentException($"Expected {nameof(expression)} to be of type {nameof(MemberExpression)}\r\n\t{expression}", nameof(expression));
}
return(memberExpression.GetValue(jsonSerializerSettings));
}
case ExpressionType.New:
{
NewExpression newExpression = expression as NewExpression;
if (newExpression == null)
{
throw new ArgumentException($"Expected {nameof(expression)} to be of type {nameof(NewExpression)}\r\n\t{expression}", nameof(expression));
}
return(newExpression.GetValue(jsonSerializerSettings));
}
case ExpressionType.Not:
{
UnaryExpression unaryExpression = expression as UnaryExpression;
if (unaryExpression == null)
{
throw new ArgumentException($"Expected {nameof(expression)} to be of type {nameof(UnaryExpression)}\r\n\t{expression}", nameof(expression));
}
object unaryValue = unaryExpression.GetValue(jsonSerializerSettings);
if (unaryValue == null ||
(unaryValue.GetType() != typeof(bool) && unaryValue.GetType() != typeof(bool?)))
{
throw new ArgumentException($"Invalid type", nameof(expression));
}
return(!((bool)unaryValue));
}
case ExpressionType.Parameter:
{
ParameterExpression parameterExpression = expression as ParameterExpression;
if (parameterExpression == null)
{
throw new ArgumentException($"Expected {nameof(expression)} to be of type {nameof(ParameterExpression)}\r\n\t{expression}", nameof(expression));
}
throw new ArgumentException($"Invalid expression type {expression.NodeType}\r\n\t{expression}", nameof(expression));
}
case ExpressionType.NewArrayInit:
{
NewArrayExpression newArrayExpression = expression as NewArrayExpression;
if (newArrayExpression == null)
{
throw new ArgumentException($"Expected {nameof(expression)} to be of type {nameof(NewArrayExpression)}\r\n\t{expression}", nameof(expression));
}
return(newArrayExpression.Expressions.Select(_ => _.GetValue(jsonSerializerSettings)).ToArray());
}
default:
throw new ArgumentException($"Invalid expression type {expression.NodeType}\r\n\t{expression}", nameof(expression));
}
}
public static object GetValue(this Expression expression)
{
if (expression == null)
{
throw new ArgumentNullException(nameof(expression));
}
switch (expression.NodeType)
{
case ExpressionType.Constant:
{
ConstantExpression constantExpression = expression as ConstantExpression;
if (constantExpression == null)
{
throw new ArgumentException($"Expected {nameof(expression)} to be of type {nameof(ConstantExpression)}\r\n\t{expression}", nameof(expression));
}
return(constantExpression.GetValue());
}
case ExpressionType.Call:
{
MethodCallExpression methodCallExpression = expression as MethodCallExpression;
if (methodCallExpression == null)
{
throw new ArgumentException($"Expected {nameof(expression)} to be of type {nameof(MethodCallExpression)}\r\n\t{expression}", nameof(expression));
}
return(methodCallExpression.GetValue());
}
case ExpressionType.Convert:
{
UnaryExpression unaryExpression = expression as UnaryExpression;
if (unaryExpression == null)
{
throw new ArgumentException($"Expected {nameof(expression)} to be of type {nameof(UnaryExpression)}\r\n\t{expression}", nameof(expression));
}
return(unaryExpression.GetValue());
}
case ExpressionType.MemberAccess:
{
MemberExpression memberExpression = expression as MemberExpression;
if (memberExpression == null)
{
throw new ArgumentException($"Expected {nameof(expression)} to be of type {nameof(MemberExpression)}\r\n\t{expression}", nameof(expression));
}
return(memberExpression.GetValue());
}
case ExpressionType.New:
{
NewExpression newExpression = expression as NewExpression;
if (newExpression == null)
{
throw new ArgumentException($"Expected {nameof(expression)} to be of type {nameof(NewExpression)}\r\n\t{expression}", nameof(expression));
}
return(newExpression.GetValue());
}
default:
throw new ArgumentException($"Invalid expression type {expression.NodeType}\r\n\t{expression}", nameof(expression));
}
}
