public string ParseLambdaExpression <TEntity>(Expression <Func <TEntity, bool> > expr)
{
lock (_locker)
{
_variables = null;
return(ParseExpressionTree(string.Empty, ExpressionTreeHelpers.ToBinary(expr.Body)));
}
}
private string ParseExpressionTree(string result, BinaryExpression bin)
{
if (bin.NodeType == ExpressionType.OrElse || bin.NodeType == ExpressionType.Or)
{
return($"{result}({ParseExpressionTree(result, ExpressionTreeHelpers.ToBinary(bin.Left))}) or ({ParseExpressionTree(result, ExpressionTreeHelpers.ToBinary(bin.Right))})");
}
if (bin.NodeType == ExpressionType.AndAlso || bin.NodeType == ExpressionType.And)
{
return($"{result}({ParseExpressionTree(result, ExpressionTreeHelpers.ToBinary(bin.Left))}) and ({ParseExpressionTree(result, ExpressionTreeHelpers.ToBinary(bin.Right))})");
}
if (ExpressionTreeHelpers.Operators.Contains(bin.NodeType))
{
string lhs = bin.Left.ToString(), rhs = bin.Right.ToString();
if (bin.Right is MemberExpression member)
{
EvaluateMember(member, bin, out rhs);
}
if (bin.Left.NodeType == ExpressionType.Convert || bin.Right.NodeType == ExpressionType.Convert)
{
ConvertNode(bin, out lhs, out rhs);
}
if (bin.Right.NodeType == ExpressionType.Not)
{
rhs = HandleNotExpression(bin);
}
return($"{result}{lhs} {ExpressionTreeHelpers.GetOperator(bin.NodeType)} {rhs?.Replace(@"""", "'")}");
}
return(string.Empty);
}