反射：修改请求头HttpWebRequest/Webclient Header属性的date值-

您可以使用以下代码来修改HttpWebRequest的Header属性中的date值：

HttpWebRequest request = (HttpWebRequest)WebRequest.Create(url);
request.Method = "GET";
request.Headers["date"] = DateTime.UtcNow.ToString("r");

这里使用了DateTime.UtcNow来获取当前的UTC时间，并将其转化为"r"格式的字符串，然后将其赋值给Header属性中的date键值对。

同样的，如果您想要修改WebClient的Header属性中的date值，可以使用以下代码：

WebClient client = new WebClient();
client.Headers["date"] = DateTime.UtcNow.ToString("r");
string result = client.DownloadString(url);

这里也是使用了DateTime.UtcNow来获取当前的UTC时间，并将其转化为"r"格式的字符串，然后将其赋值给Header属性中的date键值对。

相关问题

C# 验证http://192.168.1.220:8080////Images/心电图/2023-12/01/1222200108/0702/927aec89-db4a-4880-a0a6-fc5189047907.jpg网络路径图片是否存在

以下是C#验证网络路径图片是否存在的代码：

using System.Net;

public bool CheckImageExists(string imageUrl)
{
    try
    {
        HttpWebRequest request = (HttpWebRequest)WebRequest.Create(imageUrl);
        request.Method = "HEAD";
        HttpWebResponse response = (HttpWebResponse)request.GetResponse();
        return response.StatusCode == HttpStatusCode.OK;
    }
    catch
    {
        return false;
    }
}

你可以将需要验证的图片的URL传递给CheckImageExists方法，如果返回值为true，则表示该图片存在于该URL中，否则表示该图片不存在。

--相关问题--:
1. 如何在C#中下载网络图片？
2. 如何在C#中获取网络图片的大小？
3. 如何在C#中获取网络图片的格式？

vb.net 实现如下请求，应该怎么写？ POST /RTService/service.asmx HTTP/1.1 Host: 10.168.1.137 Content-Type: text/xml; charset=utf-8 Content-Length: length SOAPAction: "http://tempuri.org/SpcCheck" <?xml version="1.0" encoding="utf-8"?> <soap:Envelope xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xmlns:xsd="http://www.w3.org/2001/XMLSchema" xmlns:soap="http://schemas.xmlsoap.org/soap/envelope/"> <soap:Body> <SpcCheck xmlns="http://tempuri.org/"> <dcs> <DataCollection> <BatchIDs>string</BatchIDs> <WaferIDs>string</WaferIDs></DataCollection> </dcs> </SpcCheck> </soap:Body> </soap:Envelope>

你可以使用VB.Net中的HttpWebRequest和HttpWebResponse类来实现该请求。具体实现过程如下：

Dim request As HttpWebRequest = CType(WebRequest.Create("http://10.168.1.137/RTService/service.asmx"), HttpWebRequest)
request.Method = "POST"
request.ContentType = "text/xml; charset=utf-8"
request.Headers.Add("SOAPAction", "http://tempuri.org/SpcCheck")

Dim xml As String = "<?xml version=""1.0"" encoding=""utf-8""?>" & _
        "<soap:Envelope xmlns:xsi=""http://www.w3.org/2001/XMLSchema-instance"" " & _
        "xmlns:xsd=""http://www.w3.org/2001/XMLSchema"" " & _
        "xmlns:soap=""http://schemas.xmlsoap.org/soap/envelope/"">" & _
        "<soap:Body>" & _
        "<SpcCheck xmlns=""http://tempuri.org/"">" & _
        "<dcs>" & _
        "<DataCollection>" & _
        "<BatchIDs>string</BatchIDs>" & _
        "<WaferIDs>string</WaferIDs>" & _
        "</DataCollection>" & _
        "</dcs>" & _
        "</SpcCheck>" & _
        "</soap:Body>" & _
        "</soap:Envelope>"

Dim data As Byte() = Encoding.UTF8.GetBytes(xml)
request.ContentLength = data.Length

Using stream As Stream = request.GetRequestStream()
    stream.Write(data, 0, data.Length)
End Using

Dim response As HttpWebResponse = CType(request.GetResponse(), HttpWebResponse)
Dim reader As StreamReader = New StreamReader(response.GetResponseStream())
Dim result As String = reader.ReadToEnd()

Console.WriteLine(result)

这段代码发送了一个POST请求，将请求体设置为xml变量中的内容，然后从响应流中读取响应并输出。你需要将`10.168.1.137`替换为实际的IP地址，以及将`string`替换为实际的数据。