asp.net webform 允许跨域

void Application_BeginRequest(object sender, EventArgs e)
{
    // 允许跨域请求的域名列表，可以根据需求进行修改
    string[] allowedOrigins = new string[] { "http://example1.com", "http://example2.com" };
    
    // 获取请求来源
    string origin = HttpContext.Current.Request.Headers["Origin"];

    // 检查请求来源是否在允许的域名列表中
    if (!string.IsNullOrEmpty(origin) && allowedOrigins.Contains(origin))
    {
        // 设置允许跨域的响应头
        HttpContext.Current.Response.AddHeader("Access-Control-Allow-Origin", origin);
        HttpContext.Current.Response.AddHeader("Access-Control-Allow-Methods", "GET, POST, PUT, DELETE, OPTIONS");
        HttpContext.Current.Response.AddHeader("Access-Control-Allow-Headers", "Content-Type");
        HttpContext.Current.Response.AddHeader("Access-Control-Allow-Credentials", "true");
    }

    // 处理预检请求（OPTIONS 请求）
    if (HttpContext.Current.Request.HttpMethod == "OPTIONS")
    {
        HttpContext.Current.Response.StatusCode = 200;
        HttpContext.Current.Response.End();
    }
}

 要允许所有，使用下面代码 ：

Response.AppendHeader("Access-Control-Allow-Origin", "*"); // 允许来自任何域的请求
Response.AppendHeader("Access-Control-Allow-Methods", "POST"); // 允许的请求方法
Response.AppendHeader("Access-Control-Allow-Headers", "Content-Type"); // 允许的请求头