Brian Vander Plaats
Developer
LINQ Cheat Sheet
Developer
LINQ is a query language in C# and VB.NET designed for querying and updating data. This data could include an array, object, database, file, etc.
var query = from m in Manufacturers
where m.Name == "Trek"
select m;
var lambda = Manufacturers.Where(m => m.Name == "Trek").Select(m => m);
Dim query = from m in Manufacturers
where m.Name = "Trek"
select m
Dim lambda = Manufacturers.Where(function(m) m.Name = "Trek").Select(function(m) m)
var query = from m in Manufacturers
where m.Name == "Trek"
select new {Name = m.Name, Key = m.ManufacturerId};
var lambda = Manufacturers.Where(m => m.Name == "Trek").Select(m=> new {Name = m.Name, Key = m.ManufacturerId});
Dim query = from m in Manufacturers
where m.Name = "Trek"
select new with {.Name = m.Name, .ManufacturerId = m.ManufacturerId}
Dim lambda = Manufacturers.Where(function(m) m.Name = "Trek").Select(function(m) new with {.Name = m.Name, .ManufacturerId = m.ManufacturerId})
var query = from m in Models
join p in PartNumbers on m.ModelId equals p.ModelId
where m.Name.Contains("Domane")
select new {m.ModelId, ModelName = m.Name, PartNumber = p.InventoryPartNumber };
var lambda = Models.Join(PartNumbers, m => m.ModelId, p => p.ModelId, (m, p) => new {m = m, p = p} )
.Where( j => j.m.Name.Contains("Domane"))
.Select(j => new {ModelId = j.m.ModelId, ModelName = j.m.Name, PartNumber = j.p.InventoryPartNumber});
Dim query = from m in Models
join p in PartNumbers on m.ModelId equals p.ModelId
where m.Name.Contains("Domane")
select new with {.ModelId = m.ModelId, .ModelName = m.Name, .PartNumber = p.InventoryPartNumber }
Dim lambda = Models.Join(PartNumbers, function(m) m.ModelId, function(p) p.ModelId, function(m,p) new with {.m = m, .p = p} ) _
.Where( function(j) j.m.Name.Contains("Domane")) _
.Select(function(j) new with {.ModelId = j.m.ModelId, .ModelName = j.m.Name, .PartNumber = j.p.InventoryPartNumber})
// Single() will throw an error if more than one result, or there is no result
var lambda = Statuses.Single( s => s.Name == "Active");
// SingleorDefault() will throw an error if more than one result, and null if there is no result
var lambda = Statuses.SingleOrDefault( s => s.Name == "Active");
// first() will throw an error if no results
var lambda = PartNumbers.First( p => p.ModelId == 10001);
//firstOrDefault will return null if no results
var lambda = PartNumbers.FirstOrDefault( p => p.ModelId == 10001);
var lambda = PartNumbers.FirstOrDefault();
'Single() will throw an error if more than one result, or there is no result
Dim lambda = Statuses.Single( function(s) s.Name = "Active")
'SingleorDefault() will throw an error if more than one result, and null if there is no result
Dim lambda = Statuses.SingleOrDefault( function(s) s.Name = "Active")
'first() will throw an error if no results
Dim lambda = PartNumbers.First( function(p) p.ModelId = 10001)
'firstOrDefault will return null if no results
Dim lambda = PartNumbers.FirstOrDefault( function(p) p.ModelId = 10001)
Dim lambda = PartNumbers.FirstOrDefault()