方法必须在非泛型静态类中定义
本文关键字：静态类 定义 泛型 方法 | 更新日期: 2023-09-27 18:13:44
我是c#新手，我的类有这个错误。
Extension method must be defined in a non-generic static class
我刚刚搜索并发现了许多可能导致此错误的原因，例如将静态添加到类名等，您可以帮助我找到为什么这个错误出现在类中吗?
using System;
using System.Collections.Generic;
using System.Text.RegularExpressions;
namespace LandManagment
{
class weather
{
private string xml;
private string FullTextXML;
private string PartTextXML;
public List<Forcast> forcastlist;
public Wind wind;
public Astronomy astronomy;
public Atmosphere atmosphere;
public Condition condition;
public struct Forcast
{
public Forcast(string day, string date, string low, string high, string text, string code)
{
Day = day;
Date = date;
Low = low;
High = high;
Text = text;
Code = code;
}
public string Day { get; private set; }
public string Date { get; private set; }
public string Low { get; private set; }
public string High { get; private set; }
public string Text { get; private set; }
public string Code { get; private set; }
}
public struct Wind
{
public Wind(string chill, string direction, string speed)
{
Chill = chill;
Direction = direction;
Speed = speed;
}
public string Chill { get; private set; }
public string Direction { get; private set; }
public string Speed { get; private set; }
}
public struct Astronomy
{
public Astronomy(string sunrise, string sunset)
{
Sunrise = sunrise;
Sunset = sunset;
}
public string Sunrise { get; private set; }
public string Sunset { get; private set; }
}
public struct Atmosphere
{
public Atmosphere(string humidity, string visibility, string pressure, string rising)
{
Humidity = humidity;
Visibility = visibility;
Pressure = pressure;
Rising = rising;
}
public string Humidity { get; private set; }
public string Visibility { get; private set; }
public string Pressure { get; private set; }
public string Rising { get; private set; }
}
public struct Condition
{
public Condition(string text, string code, string temp)
{
Text = text;
Code = code;
Temp = temp;
}
public string Text { get; private set; }
public string Code { get; private set; }
public string Temp { get; private set; }
}
private string GetStr(string str) {
try {
int index1;
int index2;
index1 = (str.IndexOf("<![CDATA[") + "<![CDATA[".Length);
index2 = str.IndexOf("]]>");
string str1 = str.Substring(index1, (index2 - index1));
// MsgBox(str1)
return str1;
}
catch (Exception ex) {
return "Error";
}
}
private string getXML() {
return FullTextXML;
}
private void GetWind() {
int index1;
int index2;
string NewString;
index1 = (PartTextXML.IndexOf("<yweather:wind") + "<yweather:wind".Length);
NewString = PartTextXML.Substring(index1);
index2 = NewString.IndexOf("/>");
string TodayWind= NewString.Substring(0, index2).ToLower();
//speed
index1 = TodayWind.IndexOf("speed");
string NewStr = TodayWind.Substring(index1);
index2 = NewStr.IndexOf(" ");
string ss = NewStr.Substring(0, index2);
string[] arr = ss.Split('=');
string speed = FormatString(arr[1].Replace("'"", ""));
//direction
index1 = TodayWind.IndexOf("direction");
NewStr = TodayWind.Substring(index1);
index2 = NewStr.IndexOf(" ");
ss = NewStr.Substring(0, index2);
arr = ss.Split('=');
string direction = FormatString(arr[1].Replace("'"", ""));
//chill
index1 = TodayWind.IndexOf("chill");
NewStr = TodayWind.Substring(index1);
index2 = NewStr.IndexOf(" ");
ss = NewStr.Substring(0, index2);
arr = ss.Split('=');
string chill = FormatString(arr[1].Replace("'"", ""));
wind = new Wind(speed, direction, chill);
}
public void GetAstronomy() {
int index1;
int index2;
string NewString;
index1 = (PartTextXML.IndexOf("<yweather:astronomy") + "<yweather:astronomy".Length);
NewString = PartTextXML.Substring(index1);
index2 = NewString.IndexOf("/>");
String TodayAstronomy = NewString.Substring(0, index2).ToLower();
//sunrise
index1 = TodayAstronomy.IndexOf("sunrise");
string NewStr = TodayAstronomy.Substring(index1);
index2 = NewStr.IndexOf(" am");
string ss = NewStr.Substring(0, index2);
string[] arr = ss.Split('=');
String sunrise = (FormatString(arr[1].Replace("'"", "")) + "am");
//sunset
index1 = TodayAstronomy.IndexOf("sunset");
NewStr = TodayAstronomy.Substring(index1);
index2 = NewStr.IndexOf(" pm");
ss = NewStr.Substring(0, index2);
arr = ss.Split('=');
String sunset = (FormatString(arr[1].Replace("'"", "")) + "pm");
astronomy = new Astronomy(sunrise, sunset);
}
private void GetAtmosphere()
{
int index1;
int index2;
string NewString;
index1 = (PartTextXML.IndexOf("<yweather:atmosphere") + "<yweather:atmosphere".Length);
NewString = PartTextXML.Substring(index1);
index2 = NewString.IndexOf("/>");
string TodayAtmosphere = NewString.Substring(0, index2).ToLower();
//humidity
index1 = TodayAtmosphere.IndexOf("humidity");
string NewStr = TodayAtmosphere.Substring(index1);
index2 = NewStr.IndexOf(" ");
string ss = NewStr.Substring(0, index2);
string[] arr = ss.Split('=');
string humidity = FormatString(arr[1].Replace("'"", ""));
//visibility
index1 = TodayAtmosphere.IndexOf("visibility");
NewStr = TodayAtmosphere.Substring(index1);
index2 = NewStr.IndexOf(" ");
ss = NewStr.Substring(0, index2);
arr = ss.Split('=');
string visibility = FormatString(arr[1].Replace("'"", ""));
//pressure
index1 = TodayAtmosphere.IndexOf("pressure");
NewStr = TodayAtmosphere.Substring(index1);
index2 = NewStr.IndexOf(" ");
ss = NewStr.Substring(0, index2);
arr = ss.Split('=');
string pressure = FormatString(arr[1].Replace("'"", ""));
//rising
index1 = TodayAtmosphere.IndexOf("rising");
NewStr = TodayAtmosphere.Substring(index1);
index2 = NewStr.IndexOf(" ");
ss = NewStr.Substring(0, index2);
arr = ss.Split('=');
string rising = FormatString(arr[1].Replace("'"", ""));
atmosphere = new Atmosphere(humidity, visibility, pressure, rising);
}
private void GetCondition()
{
int index1;
int index2;
string NewString;
index1 = (PartTextXML.IndexOf("<yweather:condition") + "<yweather:condition".Length);
NewString = PartTextXML.Substring(index1);
index2 = NewString.IndexOf("/>");
String TodayCondition = NewString.Substring(0, index2).ToLower();
//temp
index1 = TodayCondition.IndexOf("temp");
string NewStr = TodayCondition.Substring(index1);
index2 = NewStr.IndexOf(" ");
string ss = NewStr.Substring(0, index2);
string[] arr = ss.Split('=');
string temp = FormatString(arr[1].Replace("'"", ""));
//code
index1 = TodayCondition.IndexOf("code");
NewStr = TodayCondition.Substring(index1);
index2 = NewStr.IndexOf(" ");
ss = NewStr.Substring(0, index2);
arr = ss.Split('=');
string code = FormatString(arr[1].Replace("'"", ""));
//text
index1 = TodayCondition.IndexOf("text");
NewStr = TodayCondition.Substring(index1);
index2 = NewStr.IndexOf(" ");
ss = NewStr.Substring(0, index2);
arr = ss.Split('=');
string text = FormatString(arr[1].Replace("'"", ""));
condition = new Condition(text, code, temp);
}
public void GetForecast()
{
for (int i = 0; i < 2; i++)
{
int index1;
int index2;
string NewString;
index1 = (NthIndexOf(PartTextXML, "<yweather:astronomy", i+1) + "<yweather:astronomy".Length);
NewString = PartTextXML.Substring(index1);
index2 = NewString.IndexOf("/>");
string forc=NewString.Substring(0, index2).ToLower();
//low
index1 = forc.IndexOf("low");
string NewStr = forc.Substring(index1);
index2 = NewStr.IndexOf(" ");
string ss = NewStr.Substring(0, index2);
string[] arr = ss.Split('=');
String Low = arr[1].Replace("'"", "");
//high
index1 = forc.IndexOf("high");
NewStr = forc.Substring(index1);
index2 = NewStr.IndexOf(" ");
ss = NewStr.Substring(0, index2);
arr = ss.Split('=');
String High = arr[1].Replace("'"", "");
//text
index1 = forc.IndexOf("text");
NewStr = forc.Substring(index1);
index2 = NewStr.IndexOf(" ");
ss = NewStr.Substring(0, index2);
arr = ss.Split('=');
String text = arr[1].Replace("'"", "");
//text
index1 = forc.IndexOf("code");
NewStr = forc.Substring(index1);
index2 = NewStr.IndexOf(" ");
ss = NewStr.Substring(0, index2);
arr = ss.Split('=');
String code = arr[1].Replace("'"", "");
//day
index1 = forc.IndexOf("day");
NewStr = forc.Substring(index1);
index2 = NewStr.IndexOf(" ");
ss = NewStr.Substring(0, index2);
arr = ss.Split('=');
String day = arr[1].Replace("'"", "");
//date
index1 = forc.IndexOf("date");
NewStr = forc.Substring(index1);
index2 = NewStr.IndexOf(" ");
ss = NewStr.Substring(0, index2);
arr = ss.Split('=');
String date = arr[1].Replace("'"", "");
forcastlist.Insert(i,new Forcast(day,date,Low,High,text,code));
}
}
private static int NthIndexOf(this string target, string value, int n)
{
Match m = Regex.Match(target, "((" + value + ").*?){" + n + "}");
if (m.Success)
return m.Groups[2].Captures[n - 1].Index;
else
return -1;
}
public weather(string w, string U) {
System.Xml.XmlDocument doc = new System.Xml.XmlDocument();
string str = ("http://xml.weather.yahoo.com/forecastrss?w="
+ (w + ("&u=" + U)));
try {
// Load data
doc.Load(str);
str = doc.OuterXml;
FullTextXML = doc.OuterXml;
PartTextXML = GetStr(str);
this.GetAstronomy();
this.GetAtmosphere();
this.GetCondition();
this.GetForecast();
}
catch (Exception ex) {
str = "null";
FullTextXML = "null";
throw new Exception("Null XML");
}
}
private string FormatString(String sss) {
char c = sss[0];
c = c.ToString().ToUpper()[0];
string str="";
str = (c + sss.Substring(1));
return str;
}
}
}
我试图改变public static class作为扩展方法必须定义在非泛型静态类说，但得到错误:(谢谢你的帮助
由于NthIndexOf是一个扩展方法，所以需要在public static class中定义。我怀疑你把weather变成了public static class。
public static class weather
{
}
但是，这不起作用，因为weather包含非静态实例成员，例如
private string xml;
private string FullTextXML;
private string PartTextXML;
public List<Forcast> forcastlist;
// etc...
public static class StringExtensions
{
public static int NthIndexOf(this string target, string value, int n)
{
Match m = Regex.Match(target, "((" + value + ").*?){" + n + "}");
if (m.Success)
return m.Groups[2].Captures[n - 1].Index;
else
return -1;
}
}
你可以像这样从你的weather类调用它:
int y = PartTextXML.NthIndexOf("<yweather:astronomy", i + 1);
你必须放置这个方法:
private static int NthIndexOf(this string target, string value, int n)
{
Match m = Regex.Match(target, "((" + value + ").*?){" + n + "}");
// I changed a bit your code here.
return m.Success ? m.Groups[2].Captures[n - 1].Index : -1;
}
在静态类中。这是一个extension方法，所有的扩展方法都应该放在static类中。如果你调用这个调用Extensions，那么它应该像下面这样:
static public class Extension
{
public static int NthIndexOf(this string target, string value, int n)
{
Match m = Regex.Match(target, "((" + value + ").*?){" + n + "}");
if (m.Success)
return m.Groups[2].Captures[n - 1].Index;
else
return -1;
}
}
如何调用扩展方法?
input.NthIndexOf(value, n);
其中input是我们的字符串。
有关扩展方法的更多信息，请查看此处
您的NthIndexOf方法不在静态类中-为了使扩展方法工作，它们必须在静态类中定义。
1 -按照上面的正确答案，将"NthIndexOf"函数移动到一个公共静态类中。
public static class StringExtensions
{
public static int NthIndexOf(this string target, string value, int n)
{
Match m = Regex.Match(target, "((" + value + ").*?){" + n + "}");
if (m.Success)
return m.Groups[2].Captures[n - 1].Index;
else
return -1;
}
}
2 -在GetForecast函数中，将调用函数的位置更改为
代替:
index1 = (NthIndexOf(PartTextXML, "<yweather:astronomy", i+1) + "<yweather:astronomy".Length);
这样做:
index1 = (StringExtensions.NthIndexOf(PartTextXML, "<yweather:astronomy", i+1) + "<yweather:astronomy".Length);