Question

Partial Class Default2
    Inherits System.Web.UI.Page

    Private Sub form1_Load(sender As Object, e As EventArgs) Handles form1.Load

        Dim Flagimageurl(6) As String ' creating the flag image url array'
        Flagimageurl(0) = "https://www.cia.gov/library/publications/the-world-factbook/graphics/flags/large/uk-lgflag.gif"
        Flagimageurl(1) = "https://upload.wikimedia.org/wikipedia/en/thumb/c/c3/Flag_of_France.svg/800px-Flag_of_France.svg.png"
        Flagimageurl(2) = "https://upload.wikimedia.org/wikipedia/en/thumb/0/05/Flag_of_Brazil.svg/720px-Flag_of_Brazil.svg.png"
        Flagimageurl(3) = "https://upload.wikimedia.org/wikipedia/en/thumb/9/9a/Flag_of_Spain.svg/750px-Flag_of_Spain.svg.png"
        Flagimageurl(4) = "https://upload.wikimedia.org/wikipedia/en/thumb/a/a4/Flag_of_the_United_States.svg/1235px-Flag_of_the_United_States.svg.png"
        Flagimageurl(5) = "https://upload.wikimedia.org/wikipedia/commons/thumb/a/a2/Flag_of_Russia_%28Kremlin.ru%29.svg/1024px-Flag_of_Russia_%28Kremlin.ru%29.svg.png"


        Dim CountryNames(6) As String 'creating the country names array'
        CountryNames(0) = "United Kingdom"
        CountryNames(1) = "France"
        CountryNames(2) = "Brazil"
        CountryNames(3) = "Spain"
        CountryNames(4) = "United States of America (USA)"
        CountryNames(5) = "Russia"

        flag.ImageUrl = Flagimageurl(6 * Rnd()) 'Choosing a random flag'
        RadioButton1.Text = CountryNames(5 * Rnd()) 'Randomly picks the country according to the CountryNames array'
        RadioButton2.Text = CountryNames(5 * Rnd())  ' with random * 6 you get blanks so you need to use random * 5'
        RadioButton3.Text = CountryNames(5 * Rnd())
        RadioButton4.Text = CountryNames(5 * Rnd())

        If RadioButton1.Text = RadioButton2.Text Then 'Makes sure that the radiobuttons don't show duplicate answers'
            RadioButton2.Text = CountryNames(5 * Rnd())
        End If

        If RadioButton2.Text = RadioButton1.Text Then
            RadioButton1.Text = CountryNames(5 * Rnd())
        End If

        If RadioButton3.Text = RadioButton1.Text Or RadioButton3.Text = RadioButton2.Text Then
            RadioButton3.Text = CountryNames(5 * Rnd())
        End If

        If RadioButton4.Text = RadioButton1.Text Or RadioButton2.Text = RadioButton3.Text Then
            RadioButton4.Text = CountryNames(5 * Rnd())
        End If

    End Sub
End Class

问题在于，当我运行代码时，四个答案中的两个是相同的。或者它做的另一件事是它并不总是有正确的答案。

如何解决此问题？

Answer 1

首先，我会考虑使用Dictionary代替：

Dim countries As New Dictionary(Of String, String) _
    From {{"United Kingdom", "https://www.cia.gov/library/publications/the-world-factbook/graphics/flags/large/uk-lgflag.gif"},
          {"France", "https://upload.wikimedia.org/wikipedia/en/thumb/c/c3/Flag_of_France.svg/800px-Flag_of_France.svg.png"},
          {"Brazil", "https://upload.wikimedia.org/wikipedia/en/thumb/0/05/Flag_of_Brazil.svg/720px-Flag_of_Brazil.svg.png"},
          {"Spain", "https://upload.wikimedia.org/wikipedia/en/thumb/9/9a/Flag_of_Spain.svg/750px-Flag_of_Spain.svg.png"},
          {"United States of America (USA)", "https://upload.wikimedia.org/wikipedia/en/thumb/a/a4/Flag_of_the_United_States.svg/1235px-Flag_of_the_United_States.svg.png"},
          {"Russia", "https://upload.wikimedia.org/wikipedia/commons/thumb/a/a2/Flag_of_Russia_%28Kremlin.ru%29.svg/1024px-Flag_of_Russia_%28Kremlin.ru%29.svg.png"}}

然后我会使用Random类，将该项添加到另一个Dictionary并从当前Dictionary中删除该项，以便不能再次使用它。我还在循环使用六个RadioButton控件来减少代码，但您可以分开并依次执行每个RadioButton。这取决于您的设计：

Dim countriesSelected As New Dictionary(Of String, String)

Dim countryRandom As New Random
For Each rd As RadioButton In Me.Controls.OfType(Of RadioButton)()
    Dim nextRandom As Integer = countryRandom.Next(countries.Count)
    rd.Text = countries.Keys(nextRandom)
    countriesSelected.Add(countries.Keys(nextRandom), countries.Values(nextRandom))
    countries.Remove(countries.Keys(nextRandom))
Next

Dim flagRandom As New Random
flag.ImageUrl = countriesSelected.Values(flagRandom.Next(countriesSelected.Count))

输出：

如果你想在这里分开，那就是代码：

Dim countryRandom As New Random
Dim nextRandom As Integer = countryRandom.Next(countries.Count)
RadioButton1.Text = countries.Keys(nextRandom)
countriesSelected.Add(countries.Keys(nextRandom), countries.Values(nextRandom))
countries.Remove(countries.Keys(nextRandom))

nextRandom = countryRandom.Next(countries.Count)
RadioButton2.Text = countries.Keys(nextRandom)
countriesSelected.Add(countries.Keys(nextRandom), countries.Values(nextRandom))
countries.Remove(countries.Keys(nextRandom))

nextRandom = countryRandom.Next(countries.Count)
RadioButton3.Text = countries.Keys(nextRandom)
countriesSelected.Add(countries.Keys(nextRandom), countries.Values(nextRandom))
countries.Remove(countries.Keys(nextRandom))

nextRandom = countryRandom.Next(countries.Count)
RadioButton4.Text = countries.Keys(nextRandom)
countriesSelected.Add(countries.Keys(nextRandom), countries.Values(nextRandom))
countries.Remove(countries.Keys(nextRandom))

您可以看到我选择循环RadioButton控件的原因。阅读和维护起来要简单得多。

如果您真的必须使用Array，正如您在评论中所说，那么我会尝试为您做到这一点。代码是丑陋的，可能更难理解，至少在我看来它应该给你你想要的东西。

首先将(6)更改为(5)，因为这会创建6个项目。 Array基于零，因此0是第一项不是1.两个数组中的索引必须相同，以便我们在结尾选择正确的标志。

Dim Flagimageurl(5) As String ' creating the flag image url array'
Flagimageurl(0) = "https://www.cia.gov/library/publications/the-world-factbook/graphics/flags/large/uk-lgflag.gif"
Flagimageurl(1) = "https://upload.wikimedia.org/wikipedia/en/thumb/c/c3/Flag_of_France.svg/800px-Flag_of_France.svg.png"
Flagimageurl(2) = "https://upload.wikimedia.org/wikipedia/en/thumb/0/05/Flag_of_Brazil.svg/720px-Flag_of_Brazil.svg.png"
Flagimageurl(3) = "https://upload.wikimedia.org/wikipedia/en/thumb/9/9a/Flag_of_Spain.svg/750px-Flag_of_Spain.svg.png"
Flagimageurl(4) = "https://upload.wikimedia.org/wikipedia/en/thumb/a/a4/Flag_of_the_United_States.svg/1235px-Flag_of_the_United_States.svg.png"
Flagimageurl(5) = "https://upload.wikimedia.org/wikipedia/commons/thumb/a/a2/Flag_of_Russia_%28Kremlin.ru%29.svg/1024px-Flag_of_Russia_%28Kremlin.ru%29.svg.png"

Dim CountryNames(5) As String 'creating the country names array'
CountryNames(0) = "United Kingdom"
CountryNames(1) = "France"
CountryNames(2) = "Brazil"
CountryNames(3) = "Spain"
CountryNames(4) = "United States of America (USA)"
CountryNames(5) = "Russia"

我创建了一个单独的Array，试图保留已被选中的国家/地区。

Dim selectedCountries(3) As String

仍然使用Random类并循环浏览RadioButton控件，这次我们还必须遍历selectedCountries以确保我们不会重复。我初始化addCountry的值为False，在我初始化循环后将其设置为True，然后再次设置为False如果我发现该国家已经被选中。然后，这将继续循环，直到选择了新的国家/地区。

Dim countryRandom As New Random
Dim i As Integer = 0
For Each rb As RadioButton In Me.Controls.OfType(Of RadioButton)()
    Dim randomNumber As Integer

    Dim addCountry As Boolean = False
    Do While addCountry = False
        randomNumber = countryRandom.Next(CountryNames.Count)
        addCountry = True
        For Each selectedCountry In selectedCountries
            If selectedCountry = randomNumber Then
                addCountry = False
                Exit For
            End If
        Next
    Loop

    rb.Text = CountryNames(randomNumber)
    selectedCountries(i) = randomNumber
    i += 1
Next

然后我对Array：

进行排序

Array.Sort(selectedCountries)

我看一下随机数，然后检查该随机数是否在selectedCountries Array中。然后我用它：

Dim flagRandom As New Random
Dim selectedFlag As String = ""
Do While selectedFlag = ""
    Dim randomNumber As Integer = flagRandom.Next(Flagimageurl.Count)
    For Each selectedCountry In selectedCountries
        If selectedCountry = randomNumber Then
            selectedFlag = Flagimageurl(randomNumber)
        End If
    Next
Loop
flag.ImageUrl = selectedFlag

这应该会给你你所追求的，但我不能强调这段代码的实际效率。

Answer 2

这样做的一种方法是将所有If语句替换为下面的3个循环 - 这不是最好的方法，但是对于您的程序而言，它不会影响性能

代码检查按钮2,3和4与其他按钮不同。你不需要检查按钮1，因为循环将检查所有后续按钮是否与它相同。

每个循环都会从数组中选择一个新的随机文本字符串。如果它与任何其他按钮相同，它将选择另一个按钮，直到它们与所有按钮不同。

    Do While RadioButton2.Text = RadioButton1.Text Or RadioButton2.Text = RadioButton3.Text Or RadioButton2.Text = RadioButton4.Text  'Makes sure that the radiobuttons don't show duplicate answers'
        RadioButton1.Text = CountryNames(5 * Rnd())
    Loop
    Do While RadioButton3.Text = RadioButton2.Text Or RadioButton3.Text = RadioButton1.Text Or RadioButton3.Text = RadioButton4.Text  'Makes sure that the radiobuttons don't show duplicate answers'
        RadioButton1.Text = CountryNames(5 * Rnd())
    Loop
    Do While RadioButton4.Text = RadioButton2.Text Or RadioButton4.Text = RadioButton3.Text Or RadioButton4.Text = RadioButton1.Text  'Makes sure that the radiobuttons don't show duplicate answers'
        RadioButton1.Text = CountryNames(5 * Rnd())
    Loop

但是，您选择使用Rnd()将不太可能生成数字5.您最好将上述代码更改为此

    Dim randomNumber As New Random

    flag.ImageUrl = Flagimageurl(randomNumber.Next(0, 5)) 'Choosing a random flag'
    RadioButton1.Text = CountryNames(randomNumber.Next(0, 5)) 'Randomly picks the country according to the CountryNames array'
    RadioButton2.Text = CountryNames(randomNumber.Next(0, 5)) 
    RadioButton3.Text = CountryNames(randomNumber.Next(0, 5))
    RadioButton4.Text = CountryNames(randomNumber.Next(0, 5))

    Do While RadioButton2.Text = RadioButton1.Text Or RadioButton2.Text = RadioButton3.Text Or RadioButton2.Text = RadioButton4.Text  'Makes sure that the radiobuttons don't show duplicate answers'
        RadioButton1.Text = CountryNames(randomNumber.Next(0, 5))
    Loop
    Do While RadioButton3.Text = RadioButton2.Text Or RadioButton3.Text = RadioButton1.Text Or RadioButton3.Text = RadioButton4.Text  'Makes sure that the radiobuttons don't show duplicate answers'
        RadioButton1.Text = CountryNames(randomNumber.Next(0, 5))
    Loop
    Do While RadioButton4.Text = RadioButton2.Text Or RadioButton4.Text = RadioButton3.Text Or RadioButton4.Text = RadioButton1.Text  'Makes sure that the radiobuttons don't show duplicate answers'
        RadioButton1.Text = CountryNames(randomNumber.Next(0, 5))
    Loop

此代码同样可能生成所有数字。

将四个选项中的两个显示为同一个国家/地区

2 个答案: