How to upload files to a folder using C# code

Introduction

In this article, you’ll understand how to upload files to the folder using the c# code. and step by step we’ll create a Microsoft ASP.NET file (WebForm1.aspx) and its related code-behind file (WebForm1.aspx.cs) to file uploads.

Create an ASP.NET application

Let’s go to Visual Studio, follow these steps to create a new application to upload files using c#:

1. Open Visual Studio.
2. Select File menu, point to New and then click on Project.
3. In the New Project dialog box, click Visual C# Projects under Project Types, and then click ASP.NET Web Application under Templates.

In the dialog Location box, type the URL to create the project. For this example, type
http://localhost/FileUpload, which creates the default project name of FileUpload. Notice that the FileUpload.aspx file loads in the Designer view of Visual Studio .NET.

First, we have to create a WinForm like in the given code. Here is the code for FileUpload.Designer.cs file.

namespace FileUploads  
{  
    partial class FileUpload  
    {  
        /// <summary>  
        /// Required designer variable.  
        /// </summary>  
        private System.ComponentModel.IContainer components = null;  
  
        /// <summary>  
        /// Clean up any resources being used.  
        /// </summary>  
        /// <param name="disposing">true if managed resources should be disposed; otherwise, false.</param>  
        protected override void Dispose(bool disposing)  
        {  
            if (disposing && (components != null))  
            {  
                components.Dispose();  
            }  
            base.Dispose(disposing);  
        }  
 
        #region Windows Form Designer generated code  
  
        /// <summary>  
        /// Required method for Designer support - do not modify  
        /// the contents of this method with the code editor.  
        /// </summary>  
        private void InitializeComponent()  
        {  
            this.btnFile = new System.Windows.Forms.Button();  
            this.dgvFile = new System.Windows.Forms.DataGridView();  
            this.fileName = new System.Windows.Forms.DataGridViewTextBoxColumn();  
            this.filePath = new System.Windows.Forms.DataGridViewTextBoxColumn();  
            this.fileSavePath = new System.Windows.Forms.DataGridViewTextBoxColumn();  
            this.btnSave = new System.Windows.Forms.Button();  
            this.btnClear = new System.Windows.Forms.Button();  
            ((System.ComponentModel.ISupportInitialize)(this.dgvFile)).BeginInit();  
            this.SuspendLayout();  
            //   
            // btnFile  
            //   
            this.btnFile.Font = new System.Drawing.Font("Segoe UI", 9.75F, System.Drawing.FontStyle.Regular, System.Drawing.GraphicsUnit.Point, ((byte)(0)));  
            this.btnFile.Location = new System.Drawing.Point(289, 3);  
            this.btnFile.Name = "btnFile";  
            this.btnFile.Size = new System.Drawing.Size(97, 31);  
            this.btnFile.TabIndex = 10;  
            this.btnFile.Text = "....Choose File";  
            this.btnFile.UseVisualStyleBackColor = true;  
            this.btnFile.Click += new System.EventHandler(this.btnFile_Click);  
            //   
            // dgvFile  
            //   
            this.dgvFile.AllowUserToAddRows = false;  
            this.dgvFile.AllowUserToDeleteRows = false;  
            this.dgvFile.BackgroundColor = System.Drawing.SystemColors.Control;  
            this.dgvFile.ColumnHeadersHeight = 28;  
            this.dgvFile.ColumnHeadersHeightSizeMode = System.Windows.Forms.DataGridViewColumnHeadersHeightSizeMode.DisableResizing;  
            this.dgvFile.Columns.AddRange(new System.Windows.Forms.DataGridViewColumn[] {  
            this.fileName,  
            this.filePath,  
            this.fileSavePath});  
            this.dgvFile.Location = new System.Drawing.Point(2, 39);  
            this.dgvFile.Name = "dgvFile";  
            this.dgvFile.ReadOnly = true;  
            this.dgvFile.RowHeadersVisible = false;  
            this.dgvFile.RowHeadersWidth = 30;  
            this.dgvFile.Size = new System.Drawing.Size(693, 258);  
            this.dgvFile.TabIndex = 1;  
            //   
            // fileName  
            //   
            this.fileName.DataPropertyName = "cname";  
            this.fileName.HeaderText = "Name";  
            this.fileName.Name = "fileName";  
            this.fileName.ReadOnly = true;  
            this.fileName.Width = 150;  
            //   
            // filePath  
            //   
            this.filePath.DataPropertyName = "cpath";  
            this.filePath.HeaderText = "Path";  
            this.filePath.Name = "filePath";  
            this.filePath.ReadOnly = true;  
            this.filePath.Width = 250;  
            //   
            // fileSavePath  
            //   
            this.fileSavePath.DataPropertyName = "csaveto";  
            this.fileSavePath.HeaderText = "Save To";  
            this.fileSavePath.Name = "fileSavePath";  
            this.fileSavePath.ReadOnly = true;  
            this.fileSavePath.Width = 300;  
            //   
            // btnSave  
            //   
            this.btnSave.Font = new System.Drawing.Font("Segoe UI Semibold", 9.75F, System.Drawing.FontStyle.Bold, System.Drawing.GraphicsUnit.Point, ((byte)(0)));  
            this.btnSave.Location = new System.Drawing.Point(351, 304);  
            this.btnSave.Name = "btnSave";  
            this.btnSave.Size = new System.Drawing.Size(98, 32);  
            this.btnSave.TabIndex = 9;  
            this.btnSave.Text = "Save";  
            this.btnSave.UseVisualStyleBackColor = true;  
            this.btnSave.Click += new System.EventHandler(this.btnSave_Click);  
            //   
            // btnClear  
            //   
            this.btnClear.Font = new System.Drawing.Font("Segoe UI Semibold", 9.75F, System.Drawing.FontStyle.Bold, System.Drawing.GraphicsUnit.Point, ((byte)(0)));  
            this.btnClear.Location = new System.Drawing.Point(247, 304);  
            this.btnClear.Name = "btnClear";  
            this.btnClear.Size = new System.Drawing.Size(98, 32);  
            this.btnClear.TabIndex = 10;  
            this.btnClear.Text = "Clear";  
            this.btnClear.UseVisualStyleBackColor = true;  
            this.btnClear.Click += new System.EventHandler(this.btnClear_Click);  
            //   
            // FileUpload  
            //   
            this.AutoScaleDimensions = new System.Drawing.SizeF(7F, 17F);  
            this.AutoScaleMode = System.Windows.Forms.AutoScaleMode.Font;  
            this.BackColor = System.Drawing.SystemColors.Control;  
            this.ClientSize = new System.Drawing.Size(697, 345);  
            this.Controls.Add(this.btnFile);  
            this.Controls.Add(this.btnClear);  
            this.Controls.Add(this.btnSave);  
            this.Controls.Add(this.dgvFile);  
            this.Font = new System.Drawing.Font("Segoe UI", 9.75F, System.Drawing.FontStyle.Regular, 
  System.Drawing.GraphicsUnit.Point, ((byte)(0)));  
            this.Margin = new System.Windows.Forms.Padding(3, 4, 3, 4);  
            this.MaximizeBox = false;  
            this.Name = "FileUpload";  
            this.StartPosition = System.Windows.Forms.FormStartPosition.CenterScreen;  
            this.Text = "File Upload";  
            this.Load += new System.EventHandler(this.FileUpload_Load);  
            ((System.ComponentModel.ISupportInitialize)(this.dgvFile)).EndInit();  
            this.ResumeLayout(false);  
  
        }  
 
        #endregion  
        private System.Windows.Forms.DataGridView dgvFile;  
        private System.Windows.Forms.Button btnSave;  
        private System.Windows.Forms.Button btnFile;  
        private System.Windows.Forms.Button btnClear;  
        private System.Windows.Forms.DataGridViewTextBoxColumn fileName;  
        private System.Windows.Forms.DataGridViewTextBoxColumn filePath;  
        private System.Windows.Forms.DataGridViewTextBoxColumn fileSavePath;  
    }  
}  

Then, we have to declare two variables. after that, you want to save the file and another one is a data table where we store the uploaded file details.

string strSavePath = @"D:\MyFolder\";  
DataTable dtData;

Now, on the page load event, initialize that data table by calling the “CreateTable” method.

private void FileUpload_Load(object sender, EventArgs e)  
{  
    dtData = CreateTable();  
}  
  
private DataTable CreateTable()  
{  
    DataTable dtReturn = new DataTable();  
    dtReturn.Columns.Add("cname", typeof(string));  
    dtReturn.Columns.Add("cpath", typeof(string));  
    dtReturn.Columns.Add("csaveto", typeof(string));  
    return dtReturn;  
}

Here, we choose one file or multiple files to save to MyFolder.

OpenFileDialog fdlg = new OpenFileDialog();  
fdlg.Title = "Select file";  
fdlg.InitialDirectory = Environment.SpecialFolder.Desktop.ToString();          
fdlg.Filter = string.Format("{0}{1}{2} ({3})|{3}", fdlg.Filter, "", "All Files", "*.*");  
// Code for image filter  
ImageCodecInfo[] codecs = ImageCodecInfo.GetImageEncoders();  
foreach (ImageCodecInfo c in codecs)  
{  
    string codecName = c.CodecName.Substring(8).Replace("Codec", "Files").Trim();  
    fdlg.Filter = string.Format("{0}{1}{2} ({3})|{3}", fdlg.Filter, "|", codecName, c.FilenameExtension);  
}  
// Code for files filter  
fdlg.Filter = fdlg.Filter + "|CSV Files (*.csv)|*.csv";  
fdlg.Filter = fdlg.Filter + "|Excel Files (.xls ,.xlsx)|  *.xls ;*.xlsx";  
fdlg.Filter = fdlg.Filter + "|PDF Files (.pdf)|*.pdf";  
fdlg.Filter = fdlg.Filter + "|Text Files (*.txt)|*.txt";  
fdlg.Filter = fdlg.Filter + "|Word Files (.docx ,.doc)|*.docx;*.doc";  
fdlg.Filter = fdlg.Filter + "|XML Files (*.xml)|*.xml";  
  
fdlg.FilterIndex = 1;  
fdlg.RestoreDirectory = true;  
fdlg.Multiselect = true;  
if (fdlg.ShowDialog() == DialogResult.OK)  
{  
    foreach (string file in fdlg.FileNames)  
    {  
        if (file != string.Empty)  
        {  
            DataRow drRow = dtData.NewRow();  
            drRow["cname"] = Path.GetFileNameWithoutExtension(file);  
            drRow["cpath"] = file;  
            drRow["csaveto"] = strSavePath + RenameFile(file);  
            dtData.Rows.Add(drRow);  
        }  
    }  
}  
dgvFile.DataSource = dtData;

Now, let us save them to a folder using File.Copy.

File.Copy(oldPath, newPath, true);

Here is the complete code for FileUpload.cs file.

using System;  
using System.IO;  
using System.Data;  
using System.Drawing.Imaging;  
using System.Windows.Forms;  
  
namespace FileUploads  
{  
    public partial class FileUpload : Form  
    {  
        string strSavePath = @"D:\MyFolder\";  
        DataTable dtData;  
  
        public FileUpload()  
        {  
            InitializeComponent();  
        }  
          
        private void FileUpload_Load(object sender, EventArgs e)  
        {  
            dtData = CreateTable();  
        }  
  
        private DataTable CreateTable()  
        {  
            DataTable dtReturn = new DataTable();  
            dtReturn.Columns.Add("cname", typeof(string));  
            dtReturn.Columns.Add("cpath", typeof(string));  
            dtReturn.Columns.Add("csaveto", typeof(string));  
            return dtReturn;  
        }  
          
        private void btnSave_Click(object sender, EventArgs e)  
        {  
            if (dgvFile.Rows.Count > 0)  
            {  
                if (!Directory.Exists(strSavePath))  
                {  
                    Directory.CreateDirectory(strSavePath);  
                }  
                int numRes = 0;              
                for (int i = 0; i < dgvFile.Rows.Count; i++)  
                {  
                    try  
                    {  
                        string oldPath = dgvFile.Rows[i].Cells["filePath"].Value.ToString();  
                        string fileSavePath = dgvFile.Rows[i].Cells["fileSavePath"].Value.ToString();  
                        File.Copy(oldPath, fileSavePath, true);  
                        numRes++;  
                    }  
                    catch { }  
                }  
                MessageBox.Show(numRes.ToString() + " nos of file saved !");  
                dtData.Rows.Clear();  
                dgvFile.DataSource = dtData;  
            }  
        }  
  
        private void btnClear_Click(object sender, EventArgs e)  
        {  
            dtData.Rows.Clear();  
            dgvFile.DataSource = dtData;  
        }  
          
        private void btnFile_Click(object sender, EventArgs e)  
        {  
            OpenFileDialog fdlg = new OpenFileDialog();  
            fdlg.Title = "Select file";  
            fdlg.InitialDirectory = Environment.SpecialFolder.Desktop.ToString();          
            fdlg.Filter = string.Format("{0}{1}{2} ({3})|{3}", fdlg.Filter, "", "All Files", "*.*");  
            // Code for image filter  
            ImageCodecInfo[] codecs = ImageCodecInfo.GetImageEncoders();  
            foreach (ImageCodecInfo c in codecs)  
            {  
                string codecName = c.CodecName.Substring(8).Replace("Codec", "Files").Trim();  
                fdlg.Filter = string.Format("{0}{1}{2} ({3})|{3}", fdlg.Filter, "|", codecName, c.FilenameExtension);  
            }  
            // Code for files filter  
            fdlg.Filter = fdlg.Filter + "|CSV Files (*.csv)|*.csv";  
            fdlg.Filter = fdlg.Filter + "|Excel Files (.xls ,.xlsx)|  *.xls ;*.xlsx";  
            fdlg.Filter = fdlg.Filter + "|PDF Files (.pdf)|*.pdf";  
            fdlg.Filter = fdlg.Filter + "|Text Files (*.txt)|*.txt";  
            fdlg.Filter = fdlg.Filter + "|Word Files (.docx ,.doc)|*.docx;*.doc";  
            fdlg.Filter = fdlg.Filter + "|XML Files (*.xml)|*.xml";  
  
            fdlg.FilterIndex = 1;  
            fdlg.RestoreDirectory = true;  
            fdlg.Multiselect = true;  
            if (fdlg.ShowDialog() == DialogResult.OK)  
            {  
                foreach (string file in fdlg.FileNames)  
                {  
                    if (file != string.Empty)  
                    {  
                        DataRow drRow = dtData.NewRow();  
                        drRow["cname"] = Path.GetFileNameWithoutExtension(file);  
                        drRow["cpath"] = file;  
                        drRow["csaveto"] = strSavePath + RenameFile(file);  
                        dtData.Rows.Add(drRow);  
                    }  
                }  
            }  
            dgvFile.DataSource = dtData;  
        }  
  
        public string RenameFile(string filePath)  
        {  
            string strExt = Path.GetExtension(filePath);  
            string fileName = Guid.NewGuid().ToString("N") + strExt;  
            return fileName;  
        }  
    }  
}

If you want to upload files from URL, then you can use WebClient.

WebClient webClient = new WebClient();  
webClient.DownloadFileAsync(new Uri(oldPath), newPath);

Before that, you have to check if the given URL exists or not. For this, just call the URLExists method.

public bool URLExists(string url)  
{  
    bool result = true;  
    try  
    {  
        WebRequest webRequest = WebRequest.Create(url);  
        webRequest.Timeout = 1200; // miliseconds  
        webRequest.Method = "HEAD";  
        webRequest.GetResponse();  
    }  
    catch  
    {  
        result = false;  
    }  
    return result;  
}

By using these easy methods, we can upload a file or multiple files to a specific folder.

These simple tips may help beginner level readers to understand the concepts of uploading files to a folder.