AttachRolePolicyResponse

The following command attaches the AWS managed policy named ReadOnlyAccess to the IAM role named ReadOnlyRole.

To attach a managed policy to an IAM role

var client = new AmazonIdentityManagementServiceClient();
var response = client.AttachRolePolicy(new AttachRolePolicyRequest 
{
    PolicyArn = "arn:aws:iam::aws:policy/ReadOnlyAccess",
    RoleName = "ReadOnlyRole"
});