C#中怎么将int类型string类型

using System;
using System.Collections.Generic;
using System.ComponentModel;
using System.Data;
using System.Drawing;
using System.Linq;
using System.Text;
using System.Threading.Tasks;
using System.Windows.Forms;

namespace ShowValue
{
public partial class Form1 : Form
{
public Form1()
{
InitializeComponent();
}
int NgValue = 5;
private void button1_Click(object sender, EventArgs e)
{
MessageBox.Show($“{NgValue}”);
}
}
}