为什么我会在这里收到 InvalidCastException?

Why am I getting an InvalidCastException here?

我正在尝试编写代码来打印 "Row (0 to 3): "。

这是我的代码:

ReadOnly gridSize As Integer = 4
Dim s1 As String
s1 = "Row (0 to " & (gridSize - 1) & "): "
WriteLine(s1)

我在最后一行收到 InvalidCastException 错误,当机器试图打印出字符串时:

Conversion from string "Row (0 to 3): " to type 'Integer' is not valid.

整数不是字符串。 使用 gridSize.ToString() 怎么样?