启用跨域 允许所有来源

修改Startup文件

在ConfigureServices方法中添加

services.AddCors(     options => options.AddPolicy(name: "MyAllowSpecificOrigins", builder => builder.AllowAnyOrigin())     ); 

在Configure方法中添加

app.UseCors("MyAllowSpecificOrigins"); 

官方文档

https://docs.microsoft.com/zh-cn/aspnet/core/security/cors?view=aspnetcore-5.0#cors-with-named-policy-and-middleware