Question

我正在尝试使用外部html文档中的streamreader：

WebRequest request = WebRequest.Create("http://example.com/version.html");
WebResponse response = request.GetResponse();
System.IO.StreamReader reader = new System.IO.StreamReader(response.GetResponseStream());

double current = double.Parse(reader.ReadToEnd());

if (current >= 10.5)
{
    button1.Enabled = false;
}

但它抛出异常(0xc0000005) 'Access violation'

html的内容：0.10.5

我做错了什么？

编辑：

根据建议将双倍更改为版本：

WebRequest request = WebRequest.Create("http://example.com/version.html");
WebResponse response = request.GetResponse();
System.IO.StreamReader reader = new System.IO.StreamReader(response.GetResponseStream());

Version current = Version.Parse(reader.ReadToEnd());

if (current >= 0.10.5)
{
    button1.Enabled = false;
}

仍然是同样的例外：

A first chance exception of type 'System.ArgumentException' occurred in mscorlib.dll
The program '[6344] APP.vshost.exe: Program Trace' has exited with code 0 (0x0).
The program '[6344] APP.vshost.exe' has exited with code -1073741819 (0xc0000005) 'Access violation'.

Answer 1

如果您要解析的数字是版本，也许您应该考虑System.Version类，而不是double。

在字符串上调用Version.Parse。

它也可以按预期用于比较版本。

Version v1 = Version.Parse("0.10.5");
Version v2 = Version.Parse("0.11.2");

Console.WriteLine("v2 > v1 = {0}", v2 > v1);      // Outputs True
Console.WriteLine("v2 < v1 = {0}", v2 < v1);      // Outputs False

我不确定你的问题是什么。以下代码对我来说很合适（在LINQPad 4会话中）

void Main()
{
    string url = "http://m1.beatpad.net/version.html";
    var request = WebRequest.Create(url);
    var response = request.GetResponse();

    var reader = new StreamReader(response.GetResponseStream());
    var data = reader.ReadToEnd();
    var ver = Version.Parse(data);
    Console.WriteLine("{0}", ver);
}

如何将StreamReader转换为double

1 个答案: