如何在C#中将小数转换为双精度?

问题描述：

我想使用轨迹栏更改 Form 的不透明度.

I want to use a Track-Bar to change a Form's opacity.

这是我的代码:

decimal trans = trackBar1.Value / 5000;
this.Opacity = trans;

构建应用程序时，它出现以下错误:

When I build the application, it gives the following error:

Cannot implicitly convert type decimal to double

我尝试使用 trans 和 double ，但是 Control 不起作用.这段代码在过去的VB.NET项目中运行良好.

I have tried using trans and double, but then the Control doesn't work. This code worked fine in a past VB.NET project.

答

不需要像这样显式转换为 double :

An explicit cast to double like this isn't necessary:

double trans = (double) trackBar1.Value / 5000.0;

将常量标识为 5000.0 (或 5000d )就足够了:

Identifying the constant as 5000.0 (or as 5000d) is sufficient:

double trans = trackBar1.Value / 5000.0;
double trans = trackBar1.Value / 5000d;