小数点后舍入扩展时出错-无法通过实例引用进行访问；用类型名称来代替它 [英] Error with rounding extension on decimal - cannot be accessed with an instance reference; qualify it with a type name instead

问题描述

我已经使用扩展方法很多次了，还没有遇到这个问题.任何人都知道为什么会引发错误吗?

I've used extension methods numerous times, and haven't run into this issue. Anyone have any ideas why this is throwing an error?

 /// <summary>
 /// Rounds the specified value.
 /// </summary>
 /// <param name="value">The value.</param>
 /// <param name="decimals">The decimals.</param>
 /// <returns></returns>
 public static decimal Round (this decimal value, int decimals)
 {
     return Math.Round(value, decimals);
 }

用法:

decimal newAmount = decimal.Parse("3.33333333333434343434");
this.rtbAmount.Text = newAmount.Round(3).ToString();

newAmount.Round(3)引发编译器错误:

newAmount.Round(3) is throwing the compiler error:

Error   1   Member 'decimal.Round(decimal)' cannot be accessed with an instance     reference; qualify it with a type name instead

推荐答案

此处的冲突是您的扩展方法与

The conflict here is a conflict between your extension method and decimal.Round. The simplest fix here, as already discovered, is to use a different name. Methods on the type always take precedence over extension methods, even to the point of conflicting with static methods.

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