如何在C# windows应用程序表单中自动查找文件，而不需要知道目录中的文件的完整路径

using System.IO;

string[] files = Directory.GetFiles(directoryPath, fileName + fileExtension, SearchOption.AllDirectories);

foreach (string file in files)
{
    // 处理找到的文件
}

using System.IO;
using System.Windows.Forms;

namespace FileSearchExample
{
    public partial class Form1 : Form
    {
        public Form1()
        {
            InitializeComponent();
        }

        private void btnSearch_Click(object sender, EventArgs e)
        {
            string directoryPath = txtDirectory.Text;
            string fileName = txtFileName.Text;
            string fileExtension = txtFileExtension.Text;

            string[] files = Directory.GetFiles(directoryPath, fileName + fileExtension, SearchOption.AllDirectories);

            foreach (string file in files)
            {
                // 处理找到的文件
                listBox1.Items.Add(file);
            }
        }
    }
}