RSCG- part 15 – Expression Generator

 

 

name Property Expression Generator
nuget

https://www.nuget.org/packages/AOPMethodsCommon/
https://www.nuget.org/packages/AOPMethodsGenerator/

link http://msprogrammer.serviciipeweb.ro/category/roslyn/
author Andrei Ignat

This will generate code to add function to be used with Entity Framework to search for any property of a class
 

The code that you start with is

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[AutoMethods(template = TemplateMethod.CustomTemplateFile, CustomTemplateFileName = "CreateMetadata.txt")]
 
public partial class Person
 
{
 
    public int ID { get; set; }
 
    public string FirstName { get; set; }
 
    public string LastName { get; set; }
 
    public DateTime? DateOfBirth {get;set;}
 
}

The code that you will use is

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var queryCnt = Metadata_Person.expr_FirstName_Contains("9");            
 
var pers= await cnt.Person.Where(queryCnt).ToArrayAsync();
 
Console.WriteLine(pers.Length);
 
 
 
 
 
queryCnt = Metadata_Person.expr_LastName_NullOrWhite();
 
pers = await cnt.Person.Where(queryCnt).ToArrayAsync();
 
Console.WriteLine(pers.Length);
 
 
 
 
 
var queryID = Metadata_Person.expr_ID_Equal(7);
 
var pId = await cnt.Person.FirstOrDefaultAsync(queryID);
 
Console.WriteLine(pId.FirstName);
 
 
 
 
 
queryID = Metadata_Person.expr_ID_Contains(7,9);
 
pers = await cnt.Person.Where(queryID).ToArrayAsync();
 
Console.WriteLine(pers.Length);
 
 
 
 
 
var nullBirthDateQuery = Metadata_Person.expr_DateOfBirth_Null();
 
var birthNull = await cnt.Person.Where(nullBirthDateQuery).ToArrayAsync();
 
Console.WriteLine(birthNull.Length);
 
 
 
var query = Metadata_Person.FindEx("ID", SearchCriteria.Equal, 99);
 
pers = await cnt.Person.Where(query).ToArrayAsync();
 
Console.WriteLine(pers.Length);
 
 
 
query = Metadata_Person.FindEx("DateOfBirth", SearchCriteria.FindNull);
 
pers = await cnt.Person.Where(query).ToArrayAsync();
 
Console.WriteLine(pers.Length);

 

The code that is generated is

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[CompilerGenerated]                                                                                                                                               
 
public partial class Metadata_Person{
 
 
 
     
 
     
 
    //public const string prop_ID = "ID";   
 
    //public static readonly Func<Person,int> func_ID = (it=>it.ID);
 
    //public static readonly Expression<Func<Person,int>> expr_ID = (it=>it.ID);
 
    public static Expression<Func<Person,bool>> expr_ID_Equal(int value)=> (it=>it.ID == value);
 
    public static Expression<Func<Person,bool>> expr_ID_Diff(int value)=> (it=>it.ID != value);
 
    public static Expression<Func<Person,bool>> expr_ID_Contains(params int[] value)=> (it=> value.Contains(it.ID) );
 
     
 
    //int
 
     
 
     
 
     
 
     
 
     
 
         
 
    public static Expression<Func<Person,bool>> expr_ID_Greater(int value)=> (it=>it.ID > value);
 
    public static Expression<Func<Person,bool>> expr_ID_GreaterOrEqual(int value)=> (it=>it.ID >= value);
 
    public static Expression<Func<Person,bool>> expr_ID_Less(int value)=> (it=>it.ID < value);
 
    public static Expression<Func<Person,bool>> expr_ID_LessOrEqual(int value)=> (it=>it.ID <= value);
 
     
 
     
 
             
 
     
 
    //public const string prop_FirstName = "FirstName";   
 
    //public static readonly Func<Person,string> func_FirstName = (it=>it.FirstName);
 
    //public static readonly Expression<Func<Person,string>> expr_FirstName = (it=>it.FirstName);
 
    public static Expression<Func<Person,bool>> expr_FirstName_Equal(string value)=> (it=>it.FirstName == value);
 
    public static Expression<Func<Person,bool>> expr_FirstName_Diff(string value)=> (it=>it.FirstName != value);
 
    public static Expression<Func<Person,bool>> expr_FirstName_Contains(params string[] value)=> (it=> value.Contains(it.FirstName) );
 
     
 
    //string
 
     
 
     
 
         
 
    public static Expression<Func<Person,bool>> expr_FirstName_Null()=> (it=>it.FirstName == null);           
 
     
 
         
 
     
 
 
 
    public static Expression<Func<Person,bool>> expr_FirstName_NullOrWhite()=> (it=>string.IsNullOrWhiteSpace(it.FirstName));
 
 
 
    public static Expression<Func<Person,bool>> expr_FirstName_Ends(string value)=> (it=>it.FirstName.StartsWith (value));
 
    public static Expression<Func<Person,bool>> expr_FirstName_Starts(string value)=> (it=>it.FirstName.EndsWith(value));
 
    public static Expression<Func<Person,bool>> expr_FirstName_Contains(string value)=> (it=>it.FirstName.Contains(value));   
 
     
 
     
 
     
 
     
 
             
 
     
 
    //public const string prop_LastName = "LastName";   
 
    //public static readonly Func<Person,string> func_LastName = (it=>it.LastName);
 
    //public static readonly Expression<Func<Person,string>> expr_LastName = (it=>it.LastName);
 
    public static Expression<Func<Person,bool>> expr_LastName_Equal(string value)=> (it=>it.LastName == value);
 
    public static Expression<Func<Person,bool>> expr_LastName_Diff(string value)=> (it=>it.LastName != value);
 
    public static Expression<Func<Person,bool>> expr_LastName_Contains(params string[] value)=> (it=> value.Contains(it.LastName) );
 
     
 
    //string
 
     
 
     
 
         
 
    public static Expression<Func<Person,bool>> expr_LastName_Null()=> (it=>it.LastName == null);           
 
     
 
         
 
     
 
 
 
    public static Expression<Func<Person,bool>> expr_LastName_NullOrWhite()=> (it=>string.IsNullOrWhiteSpace(it.LastName));
 
 
 
    public static Expression<Func<Person,bool>> expr_LastName_Ends(string value)=> (it=>it.LastName.StartsWith (value));
 
    public static Expression<Func<Person,bool>> expr_LastName_Starts(string value)=> (it=>it.LastName.EndsWith(value));
 
    public static Expression<Func<Person,bool>> expr_LastName_Contains(string value)=> (it=>it.LastName.Contains(value));   
 
     
 
     
 
     
 
     
 
             
 
     
 
    //public const string prop_DateOfBirth = "DateOfBirth";   
 
    //public static readonly Func<Person,System.DateTime?> func_DateOfBirth = (it=>it.DateOfBirth);
 
    //public static readonly Expression<Func<Person,System.DateTime?>> expr_DateOfBirth = (it=>it.DateOfBirth);
 
    public static Expression<Func<Person,bool>> expr_DateOfBirth_Equal(System.DateTime? value)=> (it=>it.DateOfBirth == value);
 
    public static Expression<Func<Person,bool>> expr_DateOfBirth_Diff(System.DateTime? value)=> (it=>it.DateOfBirth != value);
 
    public static Expression<Func<Person,bool>> expr_DateOfBirth_Contains(params System.DateTime?[] value)=> (it=> value.Contains(it.DateOfBirth) );
 
     
 
    //System.DateTime?
 
     
 
     
 
         
 
    public static Expression<Func<Person,bool>> expr_DateOfBirth_Null()=> (it=>it.DateOfBirth == null);           
 
     
 
     
 
     
 
         
 
    public static Expression<Func<Person,bool>> expr_DateOfBirth_Greater(System.DateTime? value)=> (it=>it.DateOfBirth > value);
 
    public static Expression<Func<Person,bool>> expr_DateOfBirth_GreaterOrEqual(System.DateTime? value)=> (it=>it.DateOfBirth >= value);
 
    public static Expression<Func<Person,bool>> expr_DateOfBirth_Less(System.DateTime? value)=> (it=>it.DateOfBirth < value);
 
    public static Expression<Func<Person,bool>> expr_DateOfBirth_LessOrEqual(System.DateTime? value)=> (it=>it.DateOfBirth <= value);
 
     
 
     
 
     
 
 
 
    public static Expression<Func<Person,bool>> FindEx(string nameProp, SearchCriteria search, object value = null)
 
    {
 
         
 
         
 
         
 
        if(string.Compare("ID",nameProp,StringComparison.CurrentCultureIgnoreCase) == 0)
 
        switch(search){
 
            case SearchCriteria.None:
 
                return null;
 
             
 
            case SearchCriteria.Equal:
 
                var orig= (int) value;
 
                return expr_ID_Equal(orig);
 
            default:
 
                throw new ArgumentException("cannot find for ID case  "+search);
 
        }
 
         
 
                     
 
         
 
        if(string.Compare("FirstName",nameProp,StringComparison.CurrentCultureIgnoreCase) == 0)
 
        switch(search){
 
            case SearchCriteria.None:
 
                return null;
 
             
 
            case SearchCriteria.FindNull:
 
                return expr_FirstName_Null();
 
             
 
            case SearchCriteria.Equal:
 
                var orig= (string) value;
 
                return expr_FirstName_Equal(orig);
 
            default:
 
                throw new ArgumentException("cannot find for FirstName case  "+search);
 
        }
 
         
 
                     
 
         
 
        if(string.Compare("LastName",nameProp,StringComparison.CurrentCultureIgnoreCase) == 0)
 
        switch(search){
 
            case SearchCriteria.None:
 
                return null;
 
             
 
            case SearchCriteria.FindNull:
 
                return expr_LastName_Null();
 
             
 
            case SearchCriteria.Equal:
 
                var orig= (string) value;
 
                return expr_LastName_Equal(orig);
 
            default:
 
                throw new ArgumentException("cannot find for LastName case  "+search);
 
        }
 
         
 
                     
 
         
 
        if(string.Compare("DateOfBirth",nameProp,StringComparison.CurrentCultureIgnoreCase) == 0)
 
        switch(search){
 
            case SearchCriteria.None:
 
                return null;
 
             
 
            case SearchCriteria.FindNull:
 
                return expr_DateOfBirth_Null();
 
             
 
            case SearchCriteria.Equal:
 
                var orig= (System.DateTime?) value;
 
                return expr_DateOfBirth_Equal(orig);
 
            default:
 
                throw new ArgumentException("cannot find for DateOfBirth case  "+search);
 
        }
 
         
 
         
 
        throw new ArgumentException("cannot find property  "+nameProp);
 
         
 
    }
 
 
 
}

Example Code: https://github.com/ignatandrei/RSCG_Examples/tree/main/PropertyExpressionGenerator

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