Question

当前我有一个StringBuilder，其中有几行

        StringBuilder foo = new StringBuilder()
            .AppendLine("- one")
            .AppendLine("- two")
            .AppendLine("- three");

，我想为每个新行设置"- "字符。伪代码：

        StringBuilder foo = new StringBuilder()
            .SetNewLineInitialCharacter("- ")
            .AppendLine("one")
            .AppendLine("two")
            .AppendLine("three");

我不认为Insert或Replace是我要寻找的方法。我知道循环可以解决问题，但没有必要，我只是问是否有一种方法可以一次设置"- "。

Answer 1

许多方法之一是将StringBuilder包装在单独的类中。

void Main()
{
    var sb = new StringBuilder();
    var foo = new MyStringBuilder(sb, "- ")
            .AppendLine("one")
            .AppendLine("two")
            .AppendLine("three");

    var result = sb.ToString();
}

public class MyStringBuilder
{
    private StringBuilder _sb;
    private string _linePrefix;

    public MyStringBuilder(StringBuilder sb, string linePrefix)
    {
            _sb = sb;
            _linePrefix = linePrefix;
    }

    public MyStringBuilder AppendLine(string line)
    {
        _sb.Append(_linePrefix);
        _sb.AppendLine(line);
        return this;
    }

    public override string ToString()
    {   
       return _sb.ToString(); 
    }
}

Answer 2

您可以使用包装好的StringBuilder进行此操作：

public class StringBuilderWrapper
{
    private readonly string _prefix;
    private readonly StringBuilder _builder;

    public StringBuilderWrapper(StringBuilder builder, string prefix)
    {
        _prefix = prefix;
        _builder = builder;
    }

    public StringBuilderWrapper AppendLine(string line)
    {
        _builder.Append(_prefix);
        _builder.AppendLine(line);

        return this;
    }

    public override string ToString()
    {
        return _builder.ToString(); 
    }
}

为了方便起见，您可以从扩展方法中返回：

public static class StringBuilderExtensions
{
    public static StringBuilderWrapper SetNewLineInitialCharacter(this StringBuilder builder, string prefix)
    {
        return new StringBuilderWrapper(builder, prefix);
    }
}

然后这样称呼它：

var output = new StringBuilder()
    .SetNewLineInitialCharacter("- ")
    .AppendLine("one")
    .AppendLine("two")
    .AppendLine("three");

var outputString = output.ToString();

哪个输出：

- one
- two
- three

没有扩展方法，您可以这样称呼它：

var output = new StringBuilderWrapper(new StringBuilder(), "- ")
    .AppendLine("one")
    .AppendLine("two")
    .AppendLine("three");

Answer 3

一个简单的解决方案可能就是这样

public class CustomStringBuilder 
{
    private StringBuilder _builder;
    private string _prefix;

    public CustomStringBuilder (StringBuilder builder, string prefix)
    {
            _builder = builder;
            _prefix = prefix;
    }

    public CustomStringBuilder CustomAppendLine(string text)
    {
        _builder .Append(_prefix);
        _builder .AppendLine(text);
        return this;
    }

    public override string ToString()
    {
        return _builder.ToString(); 
    }
}

您可以这样称呼它：

CustomStringBuilderfoo = new CustomStringBuilder(new StringBuilder(), "- ")
            .CustomAppendLine ("one")
            .CustomAppendLine ("two")
            .CustomAppendLine ("three");

stringbuilder在每个新行中添加初始字符

3 个答案: