如何更改查询字符串参数的值

Question

>我有一个URL的字符串表示形式，如下所示：

http://www.GoodStuff.xxx/services/stu/query?where=1%3D1&text=&objectIds=231699%2C232002%2C231700%2C100646&time=

它是一个 URL，但在我的代码中是一个字符串对象。如何更改objectIds的值？我是否需要找到字符串，objectIds，然后找到前后的&，并将内容替换为所需的值？还是有更好的方法？

这是一个 .NET 4.5 固件控制台应用...

Answer 1

如果 URL 的其余部分是固定的，您可以手动找到 id，并使用 string.Format 和 string.Join 将 ID 插入其中：

var urlString = string.Format(
    "http://www.GoodStuff.xxx/services/stu/query?where=1%3D1&text=&objectIds={0}&time="
,   string.Join("%", ids)
);

这会将代码中以%分隔的ids列表插入到 URL 模板中。

Answer 2

如果您尝试替换已经存在的值，它会变得更加棘手。试试这个。

    //Base URL. Doesn't need to be hardcoded. As long as it contains "objectIds=" then it will work
    static string url = @"http://www.GoodStuff.xxx/services/stu/query?where=1%3D1&text=&objectIds=231699%2C232002%2C231700%2C100646&time=";

    static void Main(string[] args)
    {
        //Get the start index
        // +10 because IndexOf gets us to the o but we want the index of the equal sign
        int startIndex = url.IndexOf("objectIds=") + 10;
        //Figure out how many characters we are skipping over.
        //This is nice because then it doesn't matter if the value of objectids is 0 or 99999999
        int endIndex = url.Substring(startIndex).IndexOf('&');
        //Cache the second half of the URL
        String secondHalfOfURL = url.Substring(startIndex + endIndex); 
        //Our new IDs to stick in
        int newObjectIDs = 12345;
        //The new URL. 
        //First, we get the string up to the equal sign of the objectIds value
        //Next we put our IDS in.
        //Finally we add on the second half of the URL
        String NewURL = url.Substring(0, startIndex) + newObjectIDs + secondHalfOfURL;
        Console.WriteLine(NewURL);

        Console.Read();
    }

它不漂亮，但它可以完成工作。