C#psot请求ContentType格式为application/x-www-form-urlencoded header头里面传入值

在C#中发送POST请求并设置ContentType为application/x-www-form-urlencoded，可以使用以下代码：

using System.Net;
using System.Text;

string url = "your_url_here";
string postData = "your_post_data_here";
byte[] byteArray = Encoding.UTF8.GetBytes(postData);

WebRequest request = WebRequest.Create(url);
request.Method = "POST";
request.ContentType = "application/x-www-form-urlencoded";
request.ContentLength = byteArray.Length;

using (Stream dataStream = request.GetRequestStream())
{
    dataStream.Write(byteArray, 0, byteArray.Length);
}

using (WebResponse response = request.GetResponse())
{
    using (Stream responseStream = response.GetResponseStream())
    {
        using (StreamReader reader = new StreamReader(responseStream))
        {
            string responseText = reader.ReadToEnd();
            // Do something with the response text
        }
    }
}

在上面的代码中，你需要将`your_url_here`和`your_post_data_here`替换为你自己的URL和POST数据。在请求头中设置ContentType为application/x-www-form-urlencoded，可以通过设置`request.ContentType`来实现。在POST数据中，你需要将数据转换为字节数组并将其写入请求流中。最后，你可以通过读取响应流来获取服务器的响应。