vb.net有序集合 vb定义集合
vb.net 如何对数据库查询结果记录集排序?
加了单引号就是一个常量字符串了,对于每一行都是一样的
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像这种放在最前面的字段,order by 1 就可以了
VB.NET数组的排序法?
如果你是从vb6刚过渡上vb。net,建议还是用冒泡排序法,容易理解。
如果你正努力学习vb。net的方法,推荐一个例子如下:
Imports System
Imports System.Collections
Public Class SamplesArray
Public Class myReverserClass
Implements IComparer
' Calls CaseInsensitiveComparer.Compare with the parameters reversed.
Function Compare(x As Object, y As Object) As Integer _
Implements IComparer.Compare
Return New CaseInsensitiveComparer().Compare(y, x)
End Function 'IComparer.Compare
End Class 'myReverserClass
Public Shared Sub Main()
' Creates and initializes a new Array and a new custom comparer.
Dim myArr As [String]() = {"The", "QUICK", "BROWN", "FOX", "jumps", "over", "the", "lazy", "dog"}
Dim myComparer = New myReverserClass()
' Displays the values of the Array.
Console.WriteLine("The Array initially contains the following values:")
PrintIndexAndValues(myArr)
' Sorts a section of the Array using the default comparer.
Array.Sort(myArr, 1, 3)
Console.WriteLine("After sorting a section of the Array using the default comparer:")
PrintIndexAndValues(myArr)
' Sorts a section of the Array using the reverse case-insensitive comparer.
Array.Sort(myArr, 1, 3, myComparer)
Console.WriteLine("After sorting a section of the Array using the reverse case-insensitive comparer:")
PrintIndexAndValues(myArr)
' Sorts the entire Array using the default comparer.
Array.Sort(myArr)
Console.WriteLine("After sorting the entire Array using the default comparer:")
PrintIndexAndValues(myArr)
' Sorts the entire Array using the reverse case-insensitive comparer.
Array.Sort(myArr, myComparer)
Console.WriteLine("After sorting the entire Array using the reverse case-insensitive comparer:")
PrintIndexAndValues(myArr)
End Sub 'Main
Public Shared Sub PrintIndexAndValues(myArr() As [String])
Dim i As Integer
For i = 0 To myArr.Length - 1
Console.WriteLine(" [{0}] : {1}", i, myArr(i))
Next i
Console.WriteLine()
End Sub 'PrintIndexAndValues
End Class 'SamplesArray
'This code produces the following output.
'
'The Array initially contains the following values:
' [0] : The
' [1] : QUICK
' [2] : BROWN
' [3] : FOX
' [4] : jumps
' [5] : over
' [6] : the
' [7] : lazy
' [8] : dog
'
'After sorting a section of the Array using the default comparer:
' [0] : The
' [1] : BROWN
' [2] : FOX
' [3] : QUICK
' [4] : jumps
' [5] : over
' [6] : the
' [7] : lazy
' [8] : dog
'
'After sorting a section of the Array using the reverse case-insensitive comparer:
' [0] : The
' [1] : QUICK
' [2] : FOX
' [3] : BROWN
' [4] : jumps
' [5] : over
' [6] : the
' [7] : lazy
' [8] : dog
'
'After sorting the entire Array using the default comparer:
' [0] : BROWN
' [1] : dog
' [2] : FOX
' [3] : jumps
' [4] : lazy
' [5] : over
' [6] : QUICK
' [7] : the
' [8] : The
'
'After sorting the entire Array using the reverse case-insensitive comparer:
' [0] : the
' [1] : The
' [2] : QUICK
' [3] : over
' [4] : lazy
' [5] : jumps
' [6] : FOX
' [7] : dog
' [8] : BROWN
VB中数组怎么定义
是这么定义的:
数组中的第一个元素的下标称为下界,最后一个元素的下标称为上界,其余的元素连续地分布在上下界之间,且数组在内存中也是用连续的区域来存储的,所以数组每维的长度不能超过Long数据类型的最大值,即264—1=263。
把VB.NET数组当作一个对象来处理,就意味着数组类型是单个引用类型,数组变量包括指向构成数组元素、数组维和数组长度等数据的指针,数组之间互相赋值但仅仅是在相互复制指针,数组继承了System名字空间的Array类。
VB.NET中的数组有两种类型:定长数组和动态数组。
扩展资料:
1、数组的使用
在’VB 6.0中,能够用For Each来循环遍历一个数组。
比如:
Dim x As Integer
F0r Each x In arrayl
Console.WriteLine(x)
Next
2、在VB.NET中能够使用For循环和数组长度来遍历一个数组。
比如:
Dim i As工nteger
F0r i=0 T0 (arrayl.Length-1)
(此处空一行)
Console.WriteLine(arrayl(1)J
Next i
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