RSCG- part 15 – Expression Generator
| name | Property Expression Generator |
| nuget |
https://www.nuget.org/packages/AOPMethodsCommon/ |
| 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
[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
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
[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
Leave a Reply