我可以使用 String.Format() 用任意字符填充某个字符串吗?
Can I use String.Format() to pad a certain string with arbitrary characters?
Console.WriteLine("->{0,18}<-", "hello");
Console.WriteLine("->{0,-18}<-", "hello");
returns
-> hello<-
->hello <-
我现在希望空格是任意字符.我无法使用 padLeft 或 padRight 执行此操作的原因是因为我希望能够在不同的位置/时间构造格式字符串,然后实际执行格式化.
I now want the spaces to be an arbitrary character. The reason I cannot do it with padLeft or padRight is because I want to be able to construct the format string at a different place/time then the formatting is actually executed.
--编辑--
看到我的问题似乎没有现有的解决方案,我想出了这个(在 三思而后行的建议)
--EDIT2--
我需要一些更复杂的场景,所以我选择了 Think Before Coding 的第二条建议
[TestMethod]
public void PaddedStringShouldPadLeft() {
string result = string.Format(new PaddedStringFormatInfo(), "->{0:20:x} {1}<-", "Hello", "World");
string expected = "->xxxxxxxxxxxxxxxHello World<-";
Assert.AreEqual(result, expected);
}
[TestMethod]
public void PaddedStringShouldPadRight()
{
string result = string.Format(new PaddedStringFormatInfo(), "->{0} {1:-20:x}<-", "Hello", "World");
string expected = "->Hello Worldxxxxxxxxxxxxxxx<-";
Assert.AreEqual(result, expected);
}
[TestMethod]
public void ShouldPadLeftThenRight()
{
string result = string.Format(new PaddedStringFormatInfo(), "->{0:10:L} {1:-10:R}<-", "Hello", "World");
string expected = "->LLLLLHello WorldRRRRR<-";
Assert.AreEqual(result, expected);
}
[TestMethod]
public void ShouldFormatRegular()
{
string result = string.Format(new PaddedStringFormatInfo(), "->{0} {1:-10}<-", "Hello", "World");
string expected = string.Format("->{0} {1,-10}<-", "Hello", "World");
Assert.AreEqual(expected, result);
}
因为代码有点多,不能发帖,我把它移到github上作为要点:
http://gist.github.com/533905#file_padded_string_format_info
Because the code was a bit too much to put in a post, I moved it to github as a gist:
http://gist.github.com/533905#file_padded_string_format_info
人们可以轻松地对其进行分支和任何事情:)
There people can easily branch it and whatever :)
还有另一种解决方案.
实现 IFormatProvider
以返回将传递给 string.Format 的 ICustomFormatter
:
Implement IFormatProvider
to return a ICustomFormatter
that will be passed to string.Format :
public class StringPadder : ICustomFormatter
{
public string Format(string format, object arg,
IFormatProvider formatProvider)
{
// do padding for string arguments
// use default for others
}
}
public class StringPadderFormatProvider : IFormatProvider
{
public object GetFormat(Type formatType)
{
if (formatType == typeof(ICustomFormatter))
return new StringPadder();
return null;
}
public static readonly IFormatProvider Default =
new StringPadderFormatProvider();
}
然后你可以这样使用它:
Then you can use it like this :
string.Format(StringPadderFormatProvider.Default, "->{0:x20}<-", "Hello");
这篇关于使用任意字符串向左或向右填充 string.format(不是 padleft 或 padright)的文章就介绍到这了,希望我们推荐的答案对大家有所帮助,也希望大家多多支持跟版网!