.net core允許跨域

// 設置允許所有來源跨域
app.UseCors(options =>
{
       options.AllowAnyHeader();
       options.AllowAnyMethod();
       options.AllowAnyOrigin();
       options.AllowCredentials();
});

// 設置只允許特定來源可以跨域
app.UseCors(options =>
{
        options.WithOrigins("http://localhost:3000", "http://127.0.0.1"); // 允許特定ip跨域
        options.AllowAnyHeader();
        options.AllowAnyMethod();
        options.AllowCredentials();
});

在Startup.cs的Configure方法加如下代碼，親測好使：

        public void Configure(IApplicationBuilder app, IHostingEnvironment env)
        {
            // 設置允許所有來源跨域
            app.UseCors(options =>
            {
                options.AllowAnyHeader();
                options.AllowAnyMethod();
                options.AllowAnyOrigin();
                options.AllowCredentials();
            });

            if (env.IsDevelopment())
            {
                app.UseDeveloperExceptionPage();
            }
            else
            {
                // The default HSTS value is 30 days. You may want to change this for production scenarios, see https://aka.ms/aspnetcore-hsts.
                app.UseHsts();
            }

            app.UseHttpsRedirection();
            app.UseMvc();
        }