在下面的示例中,为什么第一个结果是 (
x
) True
而第二个结果是 (y
) False
?
Dim x = "[email protected]" Like "*symas-design.ch"
Dim y = Microsoft.VisualBasic.CompilerServices.Operators.LikeString("[email protected]", "*symas-design.ch", CompareMethod.Text)
我的目标是在 C# 中复制 VB.Net
LIKE
运算符的行为
Like
运算符显然不使用Operators.LikeString
,而是使用LikeOperator.LikeString
。
我尝试了这个LINQPad程序:
Sub Main
Dim x = "[email protected]" Like "*symas-design.ch"
Dim y = Microsoft.VisualBasic.CompilerServices.Operators.LikeString("[email protected]", "*symas-design.ch", Microsoft.VisualBasic.CompareMethod.Text)
x.Dump()
y.Dump()
End Sub
它显示:
True
False
所以正如你所说,它们不一样。但后来我展示了生成的 IL:
IL_0000: ldstr "[email protected]"
IL_0005: ldstr "*symas-design.ch"
IL_000A: ldc.i4.0
IL_000B: call Microsoft.VisualBasic.CompilerServices.LikeOperator.LikeString
IL_0010: stloc.0 // x
IL_0011: ldstr "[email protected]"
IL_0016: ldstr "*symas-design.ch"
IL_001B: ldc.i4.1
IL_001C: call Microsoft.VisualBasic.CompilerServices.Operators.LikeString
IL_0021: stloc.1 // y
IL_0022: ldloc.0 // x
IL_0023: call LINQPad.Extensions.Dump
IL_0028: pop
IL_0029: ldloc.1 // y
IL_002A: call LINQPad.Extensions.Dump
他们似乎调用了不同的方法,所以我尝试了这个:
Sub Main
Dim x = "[email protected]" Like "*symas-design.ch"
Dim y = Microsoft.VisualBasic.CompilerServices.Operators.LikeString("[email protected]", "*symas-design.ch", Microsoft.VisualBasic.CompareMethod.Text)
Dim z = Microsoft.VisualBasic.CompilerServices.LikeOperator.LikeString("[email protected]", "*symas-design.ch", Microsoft.VisualBasic.CompareMethod.Text)
x.Dump()
y.Dump()
z.Dump()
End Sub
我得到了:
True <-- Like operator
False <-- Operator.LikeString
True <-- LikeOperator.LikeString
所以你需要使用
LikeOperator.LikeString
来代替。
这里有一个 C# LINQPad 程序来演示:
void Main()
{
bool z = LikeOperator.LikeString("[email protected]", "*symas-design.ch", Microsoft.VisualBasic.CompareMethod.Text);
z.Dump();
}
还输出
True
。