private static string ExpressionTransform(this Expression expression)
{
StringBuilder result = new StringBuilder();
var candidates = new Queue <Operation>(new[] { new Operation {
Expression = expression
} });
while (candidates.Count > 0)
{
MemberExpression member = null;
ConstantExpression constant = null;
BinaryExpression binary = null;
var ope = candidates.Dequeue();
// Console.WriteLine(ope.Expression);
if (ope.Expression is BinaryExpression)
{
binary = ope.Expression as BinaryExpression;
if (binary.Left is MemberExpression && binary.Right is ConstantExpression)
{
// like n => n.PartitionKey == "42"
member = binary.Left as MemberExpression;
constant = binary.Right as ConstantExpression;
result.Insert(0, string.Format("{0} ({1} {2} {3}) ", ope.TableOperand.GetTableOperand(), member.Member.Name, binary.GetOperator(), constant.FormatConstantExpression()).TrimStart());
}
else if (binary.Left is ConstantExpression && binary.Right is MemberExpression)
{
// like n => "42" == n.PartitionKey
member = binary.Right as MemberExpression;
constant = binary.Left as ConstantExpression;
result.Insert(0, string.Format("{0} ({1} {2} {3}) ", ope.TableOperand.GetTableOperand(), member.Member.Name, binary.GetOperator(true), constant.FormatConstantExpression()).TrimStart());
}
else if (binary.Left is BinaryExpression && binary.Right is BinaryExpression)
{
// like n => n.PartitionKey == "42" && n.RowKey == 42
candidates.Enqueue(new Operation()
{
Expression = binary.Right, TableOperand = binary.NodeType
});
candidates.Enqueue(new Operation()
{
Expression = binary.Left
});
}
else if (binary.Left is MemberExpression && binary.Right is MemberExpression)
{
try
{
// like n => n.Date = DateTime.Now
member = binary.Left as MemberExpression;
result.Insert(0, string.Format("{0} ({1} {2} {3}) ", ope.TableOperand.GetTableOperand(), member.Member.Name, binary.GetOperator(), binary.Right.EvaluateExpression()).TrimStart());
}
catch
{
// like n => DateTime.Now = n.Date
member = binary.Right as MemberExpression;
result.Insert(0, string.Format("{0} ({1} {2} {3}) ", ope.TableOperand.GetTableOperand(), member.Member.Name, binary.GetOperator(true), binary.Left.EvaluateExpression()).TrimStart());
}
}
else if (binary.Left is MemberExpression && binary.Right is NewExpression)
{
// like n => n.Date = new DateTime(2012, 12, 21);
member = binary.Left as MemberExpression;
result.Insert(0, string.Format("{0} ({1} {2} {3}) ", ope.TableOperand.GetTableOperand(), member.Member.Name, binary.GetOperator(), binary.Right.EvaluateExpression()).TrimStart());
}
else if (binary.Left is NewExpression && binary.Right is MemberExpression)
{
// like n => new DateTime(2012, 12, 21) == n.Date;
member = binary.Right as MemberExpression;
result.Insert(0, string.Format("{0} ({1} {2} {3}) ", ope.TableOperand.GetTableOperand(), member.Member.Name, binary.GetOperator(true), binary.Left.EvaluateExpression()).TrimStart());
}
else if (binary.Left is MemberExpression && binary.Right is MethodCallExpression)
{
// like n => n.UniqueIdentifier == Guid.Parse("52317684-641D-40C0-86C7-9B57DF97AC7F")
member = binary.Left as MemberExpression;
result.Insert(0, string.Format("{0} ({1} {2} {3}) ", ope.TableOperand.GetTableOperand(), member.Member.Name, binary.GetOperator(), binary.Right.EvaluateExpression()).TrimStart());
}
else if (binary.Left is MethodCallExpression && binary.Right is MemberExpression)
{
// like n => n.UniqueIdentifier == Guid.Parse("52317684-641D-40C0-86C7-9B57DF97AC7F")
member = binary.Right as MemberExpression;
result.Insert(0, string.Format("{0} ({1} {2} {3}) ", ope.TableOperand.GetTableOperand(), member.Member.Name, binary.GetOperator(true), binary.Left.EvaluateExpression()).TrimStart());
}
}
else if (ope.Expression is MemberExpression)
{
// like n => n.IsEnabled
member = ope.Expression as MemberExpression;
result.Insert(0, string.Format("{0} ({1} eq true) ", ope.TableOperand.GetTableOperand(), member.Member.Name).TrimStart());
}
else if (ope.Expression is UnaryExpression)
{
var unary = ope.Expression as UnaryExpression;
// like n => !n.IsEnabled
if (unary.Operand is MemberExpression)
{
member = unary.Operand as MemberExpression;
result.Insert(0, string.Format("{0} ({1} eq false) ", ope.TableOperand.GetTableOperand(), member.Member.Name).TrimStart());
}
}
}
return(result.ToString().Trim());
}
