Welcome to OGeek Q&A Community for programmer and developer-Open, Learning and Share
Welcome To Ask or Share your Answers For Others

Categories

0 votes
334 views
in Technique[技术] by (71.8m points)

c# - How to Conditionally Format a String in .Net?

I would like to do some condition formatting of strings. I know that you can do some conditional formatting of integers and floats as follows:

Int32 i = 0;
i.ToString("$#,##0.00;($#,##0.00);Zero");

The above code would result in one of three formats if the variable is positive, negative, or zero.

I would like to know if there is any way to use sections on string arguments. For a concrete, but contrived example, I would be looking to replace the "if" check in the following code:

string MyFormatString(List<String> items, List<String> values)
{
    string itemList = String.Join(", " items.ToArray());
    string valueList = String.Join(", " values.ToArray());

    string formatString;

    if (items.Count > 0)
    //this could easily be: 
    //if (!String.IsNullOrEmpty(itemList))
    {
        formatString = "Items: {0}; Values: {1}";
    }
    else
    {
        formatString = "Values: {1}";
    }

    return String.Format(formatString, itemList, valueList);
}
See Question&Answers more detail:os

与恶龙缠斗过久,自身亦成为恶龙;凝视深渊过久,深渊将回以凝视…
Welcome To Ask or Share your Answers For Others

1 Reply

0 votes
by (71.8m points)

Well, you can simplify it a bit with the conditional operator:

string formatString = items.Count > 0 ? "Items: {0}; Values: {1}" : "Values: {1}";
return string.Format(formatString, itemList, valueList);

Or even include it in the same statement:

return string.Format(items.Count > 0 ? "Items: {0}; Values: {1}" : "Values: {1}",
                     itemList, valueList);

Is that what you're after? I don't think you can have a single format string which sometimes includes bits and sometimes it doesn't.


与恶龙缠斗过久,自身亦成为恶龙;凝视深渊过久,深渊将回以凝视…
OGeek|极客中国-欢迎来到极客的世界,一个免费开放的程序员编程交流平台!开放,进步,分享!让技术改变生活,让极客改变未来! Welcome to OGeek Q&A Community for programmer and developer-Open, Learning and Share
Click Here to Ask a Question

...