我想使用{title}代替{0} {1}等，然后以某种方式填充数据（下面我使用了一个Dictionary）。但是这段代码无效并引发异常。我想知道是否可以做类似于我想要的东西。使用{0 .. N}不是问题，我只是好奇。
Dictionary<string, string> d = new Dictionary<string, string>();
d["a"] = "he";
d["ba"] = "llo";
d["lol"] = "world";
string a = string.Format("{a}{ba}{lol}", d);
static string FormatFromDictionary(this string formatString, Dictionary<string, string> valueDict)
{
int i = 0;
StringBuilder newFormatString = new StringBuilder(formatString);
Dictionary<string, int> keyToInt = new Dictionary<string,int>();
foreach (var tuple in valueDict)
{
newFormatString = newFormatString.Replace("{" + tuple.Key + "}", "{" + i.ToString() + "}");
keyToInt.Add(tuple.Key, i);
i++;
}
return String.Format(newFormatString.ToString(), valueDict.OrderBy(x => keyToInt[x.Key]).Select(x => x.Value).ToArray());
}
formatString 中包含 "{{thing}}" 并且 ValueDict 中有一个名为 "thing" 的键将会用数字替换字符串中的 "thing"。 - Juan请看这个，它支持格式化：
public static string StringFormat(string format, IDictionary<string, object> values)
{
var matches = Regex.Matches(format, @"\{(.+?)\}");
List<string> words = (from Match matche in matches select matche.Groups[1].Value).ToList();
return words.Aggregate(
format,
(current, key) =>
{
int colonIndex = key.IndexOf(':');
return current.Replace(
"{" + key + "}",
colonIndex > 0
? string.Format("{0:" + key.Substring(colonIndex + 1) + "}", values[key.Substring(0, colonIndex)])
: values[key] == null ? string.Empty : values[key].ToString());
});
}
使用方法：
string format = "{foo} is a {bar} is a {baz} is a {qux:#.#} is a really big {fizzle}";
var dictionary = new Dictionary<string, object>
{
{ "foo", 123 },
{ "bar", true },
{ "baz", "this is a test" },
{ "qux", 123.45 },
{ "fizzle", DateTime.Now }
};
StringFormat(format, dictionary)
StringFormat("{{key}}", new Dictionary<string, object>(){["key"] = "value"}); 失败。 - Niklas Peterpublic static string StringFormat(string format, IDictionary<string, string> values)
{
foreach(var p in values)
format = format.Replace("{" + p.Key + "}", p.Value);
return format;
}
StringBuilder 可以获得更好的性能。 - datchung使用 C# 6.0 的 插值字符串，您可以做到这一点：
string name = "John";
string message = $"Hi {name}!";
//"Hi John!"
$"Hi {d["name"]}"，这应该符合 OP 的要求。 - JuanPhil Haack在他的博客上讨论了几种方法来做到这一点：http://haacked.com/archive/2009/01/14/named-formats-redux.aspx。我已经在两个项目中使用了“Hanselformat”版本，没有任何投诉。
static public class StringFormat
{
static private char[] separator = new char[] { ':' };
static private Regex findParameters = new Regex(
"\\{(?<param>.*?)\\}",
RegexOptions.Compiled | RegexOptions.Singleline);
static string FormatNamed(
this string format,
Dictionary<string, object> args)
{
return findParameters.Replace(
format,
delegate(Match match)
{
string[] param = match.Groups["param"].Value.Split(separator, 2);
object value;
if (!args.TryGetValue(param[0], out value))
value = match.Value;
if ((param.Length == 2) && (param[1].Length != 0))
return string.Format(
CultureInfo.CurrentCulture,
"{0:" + param[1] + "}",
value);
else
return value.ToString();
});
}
}
Dictionary<string, object> d = new Dictionary<string, object>();
d["a"] = DateTime.Now;
string a = string.FormatNamed("{a:yyyyMMdd-HHmmss}", d);
也会起作用...
public static string FormatFromDictionary<K, T>(this string formatString, IDictionary<K, T> valueDict)
{
if (string.IsNullOrWhiteSpace(formatString)) return formatString;
if (valueDict == null || !valueDict.Any()) return formatString;
bool escapedDoubleCurlyBraces = false;
if (formatString.Contains("{{") || formatString.Contains("}}"))
{
formatString = formatString.Replace("{{", "\\{\\{").Replace("}}", "\\}\\}");
escapedDoubleCurlyBraces = true;
}
int i = 0;
StringBuilder newFormatString = new StringBuilder(formatString);
Dictionary<K, int> keyToInt = new Dictionary<K, int>();
string field;
//StringBuilder.Replace() is faster than string.Replace().
foreach (var kvp in valueDict)
{
field = "{" + kvp.Key.ToString() + "}";
if (formatString.Contains(field))
{
newFormatString = newFormatString.Replace(field, "{" + i.ToString() + "}");
keyToInt.Add(kvp.Key, i);
i++;
}
}
//Any replacements to make?
if (keyToInt.Any())
{
formatString = string.Format(
newFormatString.ToString(),
keyToInt.OrderBy(kvp => kvp.Value).Select(kvp => (object)valueDict[kvp.Key]).ToArray()
);
}
if (escapedDoubleCurlyBraces)
{
//Converts "{{" and "}}" to single "{" and "}" for the final result just like string.format().
formatString = formatString.Replace("\\{\\{", "{").Replace("\\}\\}", "}");
}
return formatString;
}
public static string StringFormat(this string format, IDictionary<string, object> values)
{
return Regex.Matches(format, @"\{(?!\{)(.+?)\}")
.Select(m => m.Groups[1].Value)
.Aggregate(format, (current, key) =>
{
string[] splits = key.Split(":");
string replacement = splits.Length > 1
? string.Format($"{{0:{splits[1]}}}", values[splits[0]])
: values[key].ToString();
return Regex.Replace(current, "(.|^)("+ Regex.Escape($"{{{key}}}")+")(.|$)",
m => m.Groups[1].ToString() == "{" && m.Groups[3].ToString() == "}"
? m.Groups[2].ToString()
: m.Groups[1] + replacement + m.Groups[3]
);
});
}
这与另一个答案类似，但它考虑了使用{{text}}进行转义。
public static string Format(this string formatString, string[,] nameValuePairs)
{
if (nameValuePairs.GetLength(1) != 2)
{
throw new ArgumentException("Name value pairs array must be [N,2]", nameof(nameValuePairs));
}
StringBuilder newFormat = new StringBuilder(formatString);
int count = nameValuePairs.GetLength(0);
object[] values = new object[count];
for (var index = 0; index < count; index++)
{
newFormat = newFormat.Replace(string.Concat("{", nameValuePairs[index,0], "}"), string.Concat("{", index.ToString(), "}"));
values[index] = nameValuePairs[index,1];
}
return string.Format(newFormat.ToString(), values);
}
使用以下方式调用：
string format = "{foo} = {bar} (really, it's {bar})";
string formatted = format.Format(new[,] { { "foo", "Dictionary" }, { "bar", "unnecessary" } });
结果为："字典 = 不必要的（真的，它是不必要的）"
templates.Add("newField", "{id}：{name_short}，{position}")；
for (var kvp in templates) record.Add(kvp.Key, kvp.Value.FormatFromDictionary(record))； - jwatts1980