无法解析构造函数“意图”

package com.example.mukullashkari.onlinetestportal;
import android.content.Intent;
import android.support.design.widget.TabLayout;
import android.support.v4.app.Fragment;
import android.os.Bundle;
import android.support.annotation.Nullable; 
import android.view.LayoutInflater;
import android.view.View;
import android.view.ViewGroup;
import android.widget.Button;

public class Tab1_fragment extends Fragment {

Button btnC;

public static Tab1_fragment newInstance(int sectionNumber) {
    Tab1_fragment fragment = new Tab1_fragment();
    return fragment;
}

public Tab1_fragment()
{

}
@Override
public void onCreate(Bundle savedInstanceState)
{
    super.onCreate(savedInstanceState);
    btnC=(Button) btnC.findViewById(R.id.C_btn);
    btnC.setOnClickListener(new View.OnClickListener() {
        @Override
        public void onClick(View v) {
            Intent myIntent=new Intent(Tab1_fragment.this,Cassessment.class);
            startActivity(myIntent);
        }
    }

    );
}


@Nullable
@Override
public View onCreateView(LayoutInflater inflater, @Nullable ViewGroup container, Bundle savedInstanceState) {


   return inflater.inflate(R.layout.tab1_fragment,container,false);
}

}

我已经创建了 Cassessment 活动。但是错误出现在 Intent Constructor 中。说构造函数无法解析。这段代码有什么问题任何人都可以帮忙！！

错误是：：

无法解析构造函数“意图（com.example.mukullashkari.onlinetestportal.Tab1_fragment，java.lang.Class）”