Converting Expression<T, bool> to String
I need a way to recreate dynamically generated reports at some point in the future. Long story short, I need to store a specific linq query (different for each report) into databas开发者_JAVA百科e and then execute the query with dynamic Linq later on.
This is all good, but I can't find a way to convert expression to string.
As in:
Expression<Func<Product, bool>> exp = (x) => (x.Id > 5 && x.Warranty != false);
should become:
"Product.Id > 5 && Product.Warranty != false"
Is there a way to do that?
This may not be the best/most efficient method, but it does work.
Expression<Func<Product, bool>> exp = (x) => (x.Id > 5 && x.Warranty != false);
string expBody = ((LambdaExpression)exp).Body.ToString();
// Gives: ((x.Id > 5) AndAlso (x.Warranty != False))
var paramName = exp.Parameters[0].Name;
var paramTypeName = exp.Parameters[0].Type.Name;
// You could easily add "OrElse" and others...
expBody = expBody.Replace(paramName + ".", paramTypeName + ".")
.Replace("AndAlso", "&&");
Console.WriteLine(expBody);
// Output: ((Product.Id > 5) && (Product.Warranty != False))
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