本文整理汇总了VB.NET中System.Linq.Lookup<TKey,TElement>类的典型用法代码示例。如果您正苦于以下问题：VB.NET Lookup<TKey,TElement>类的具体用法？VB.NET Lookup<TKey,TElement>怎么用？VB.NET Lookup<TKey,TElement>使用的例子？那么恭喜您, 这里精选的类代码示例或许可以为您提供帮助。
在下文中一共展示了Lookup<TKey,TElement>类的1个代码示例，这些例子默认根据受欢迎程度排序。您可以为喜欢或者感觉有用的代码点赞，您的评价将有助于系统推荐出更棒的VB.NET代码示例。
示例1: LookupExample
Structure Package
Public Company As String
Public Weight As Double
Public TrackingNumber As Long
End Structure
Sub LookupExample()
' Create a list of Packages to put into a Lookup data structure.
Dim packages As New System.Collections.Generic.List(Of Package)(New Package() _
{New Package With {.Company = "Coho Vineyard", .Weight = 25.2, .TrackingNumber = 89453312L}, _
New Package With {.Company = "Lucerne Publishing", .Weight = 18.7, .TrackingNumber = 89112755L}, _
New Package With {.Company = "Wingtip Toys", .Weight = 6.0, .TrackingNumber = 299456122L}, _
New Package With {.Company = "Contoso Pharmaceuticals", .Weight = 9.3, .TrackingNumber = 670053128L}, _
New Package With {.Company = "Wide World Importers", .Weight = 33.8, .TrackingNumber = 4665518773L}})
' Create a Lookup to organize the packages. Use the first character of Company as the key value.
' Select Company appended to TrackingNumber for each element value in the Lookup.
Dim lookup As ILookup(Of Char, String) = _
packages.ToLookup(Function(ByVal p) Convert.ToChar(p.Company.Substring(0, 1)), _
Function(ByVal p) p.Company & " " & p.TrackingNumber)
Dim output As New System.Text.StringBuilder
' Iterate through each IGrouping in the Lookup and output the contents.
For Each packageGroup As IGrouping(Of Char, String) In lookup
' Print the key value of the IGrouping.
output.AppendLine(packageGroup.Key)
' Iterate through each value in the IGrouping and print its value.
For Each str As String In packageGroup
output.AppendLine(String.Format(" {0}", str))
Next
Next
' Display the output.
MsgBox(output.ToString())
' This code produces the following output:
'
' C
' Coho Vineyard 89453312
' Contoso Pharmaceuticals 670053128
' L
' Lucerne Publishing 89112755
' W
' Wingtip Toys 299456122
' Wide World Importers 4665518773
' Get the number of key-collection pairs in the Lookup.
Dim count As Integer = lookup.Count
' Select a collection of Packages by indexing directly into the Lookup.
Dim cgroup As System.Collections.Generic.IEnumerable(Of String) = lookup("C"c)
output = New System.Text.StringBuilder
' Output the results.
output.AppendLine(vbCrLf & "Packages that have a key of 'C':")
For Each str As String In cgroup
output.AppendLine(str)
Next
' Display the output.
MsgBox(output.ToString())
' This code produces the following output:
'
' Packages that have a key of 'C'
' Coho Vineyard 89453312
' Contoso Pharmaceuticals 670053128
' Determine if there is a key with the value 'G' in the Lookup.
Dim hasG As Boolean = lookup.Contains("G"c)
End Sub