https://www.cnblogs.com/wllhq/p/4330766.htmllistview显示数据库数据文章
https://www.cnblogs.com/qc-id-01/p/7489021.html选择文件及过滤文件扩展名

private void button2_Click(object sender, EventArgs e)
        {
            OpenFileDialog P_File_Folder = new OpenFileDialog();
             P_File_Folder.Multiselect = true;//该值确定是否可以选择多个文件
             P_File_Folder.Title = "请选择文件夹";
             P_File_Folder.Filter = "QQ.db(QQ.db)|QQ.db";
             if (P_File_Folder.ShowDialog() == System.Windows.Forms.DialogResult.OK)
                {
                    string file = P_File_Folder.FileName;
                    wenpath = file;
                    Console.Write(file);
                }

https://www.cnblogs.com/arxive/p/5725570.htmlrichtextbox用处