隨機數字不會附加在文本框vb.net中

Question

您好，這是我今天發現的新內容，當我創建20個字符的隨機字符串時，無法追加其他字符串

這是我的代碼

Const llen As Integer = 20 ' total 20 chars

Dim cp() As Integer = {48, 49, 50, 51, 52, 53, 54, 55, 56, 57, 65, 66, 67, 68, 69, 70, 71, 72, 73, 74, 75, 76, 77, 78, 79, 80, 81, 82, 83, 84, 85, 86, 87, 88, 89, 90}
Dim ch As Integer
Dim r As System.Random = New System.Random()

Dim rndm() As Char = New Char(llen) {}

For i As Integer = 0 To llen - 1
    ch = cp(r.Next(0, cp.Length))
    rndm(i) = Chr(ch)
Next

Dim randchars As String = rndm

Dim first As String = "CUSTOM1"

Dim second As String = "CUSTOM2"

Textbox1.Text = first & randchars & second

現在，如果我采用這種方式，輸出將不會在那些隨機字符之后附加第二個字符串

Textbox1.Text = randchars＆第二和第一

輸出僅是randchars而不是第一和第二，但是如果我在兩個字符串之后都附加randchars，它會附加什么問題？

Answer 1

好的，這可以通過將String Builder替換為Dim rndm（）來解決，如Char = New Char（llen）{}，然后追加到string builder和最后的stringbuilder.tostring