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Working With Dropbox Using C#

In this article I will explain how to work with Dropbox using C#. In this article we will do following actions

Get the list of files and folder
Create a folder in Dropbox
Delete a folder in Dropbox
Upload a file in Dropbox

First of all we need to generate token key and token secret. These will be used in the C# code when working with Dropbox.

Generate Token Key And Token Secret

First of all type this URL in the address bar of your web browser – https://www.dropbox.com/developers/apps
If you are not logged in, then a login screen will appear. Enter your email id and password.
A screen will appear to create an application. On the right hand side of the page click on ‘Create Apps’ (see the following figure)

Picture showing the Create app button for creating the dropbox application

Click to Enlarge

Enter following details and click on ‘Create app’.

Picture showing selecting the type of application

Click to Enlarge

Once the application is created Dropbox will create token key and token secret for you.

Picture showing the token key and secret generated for the application

Click to Enlarge

Now we are ready with token key and token secret, now we can write code in C#.

Adding Required Dlls

Second step is to add the reference of following 2 DLLs

Nemiro.OAuth.dll (You can download it from https://github.com/alekseynemiro/nemiro.oauth.dll)
Nemiro.OAuth.LoginForms.dll (You can download it from https://github.com/alekseynemiro/Nemiro.OAuth.LoginForms)

Once we have added the reference of the DLLs we need to add following namespace in our code

using Nemiro.OAuth;
using Nemiro.OAuth.LoginForms;

For all the actions I am using windows application in C#.

Get The List Of Files And Folder

For this action I am creating a windows application and on the windows form I am adding a listbox. Add following code in the form.

public partial class Form3: Form {
  private string CurrentPath = "/";

  public Form3() {
    InitializeComponent();
  }

  private void Form3_Load(object sender, EventArgs e) {
    var login = new DropboxLogin("token key", "token secret");
    login.Owner = this;
    login.ShowDialog();
    if (login.IsSuccessfully) {
      OAuthUtility.GetAsync("https://api.dropbox.com/1/metadata/auto",
        new HttpParameterCollection {
          {
            "path",
            CurrentPath
          }, {
            "access_token",
            login.AccessToken.Value
          }
        }, callback: GetFiles_Result
      );
    }
  }

  //  GetFiles_Result Method
  private void GetFiles_Result(RequestResult result) {
    if (this.InvokeRequired) {

      this.Invoke(new Action < RequestResult > (GetFiles_Result), result);
      return;
    }
    if (result.StatusCode == 200) {
      listBox1.Items.Clear();
      listBox1.DisplayMember = "path";
      foreach(UniValue file in result["contents"]) {
        listBox1.Items.Add(file);
      }
    }
  }
}

Here the value of this.CurrentPath is ‘/’ which means root folder. Once you run this code you will get the following popup.

Picture showing the login window of the dropbox when the code is executed

Click to Enlarge

Enter the email address and password and click on ‘Sign In’. Another window appears as shown in following figure

Picture showing he confirmation window for providing or cancelling the access on the dropbox account

Click to Enlarge

Click on ‘Allow’ button. Once you have done that you can see the list of folders and files in listbox.

Create A Folder In Dropbox

string folder_name = "gyan";
var login = new DropboxLogin("token key", "token secret");
login.Owner = this;
login.ShowDialog();
if (login.IsSuccessfully) {
  OAuthUtility.PostAsync(
    "https://api.dropbox.com/1/fileops/create_folder",
    new HttpParameterCollection {
      {
        "access_token",
        login.AccessToken.Value
      }, {
        "root",
        "auto"
      }, {
        "path",
        Path.Combine(this.CurrentPath, folder_name).Replace("\\", "/")
      }
    }, callback: CreateFolder_Result);
}

//  CreateFolder_Result
private void CreateFolder_Result(RequestResult result) {
  if (this.InvokeRequired) {
    this.Invoke(new Action < RequestResult > (CreateFolder_Result), result);
    return;
  }

  if (result.StatusCode == 200) {
    MessageBox.Show("Folder Created Successfully");
  }
}

Delete A Folder In Dropbox

string folder_name = "gyan";
var login = new DropboxLogin("token key", "token secret");
login.Owner = this;
login.ShowDialog();
if (login.IsSuccessfully) {
  OAuthUtility.PostAsync(
    "https://api.dropbox.com/1/fileops/delete",
    new HttpParameterCollection {
      {
        "access_token",
        login.AccessToken.Value
      }, {
        "root",
        "auto"
      }, {
        "path",
        folder_name
      }
    }, callback: DeleteFolder_Result);
}

//  Delete Folder_Result
private void DeleteFolder_Result(RequestResult result) {
  if (this.InvokeRequired) {
    this.Invoke(new Action < RequestResult > (DeleteFolder_Result), result);
    return;
  }

  if (result.StatusCode == 200) {
    MessageBox.Show("Folder Deleted Successfully");
  }
}

Upload A File In Dropbox

For this action we will add an openFileDialog control on the form

string CurrentPath = "/gyan";
var login = new DropboxLogin("token key", "token secret");
login.Owner = this;
login.ShowDialog();
if (login.IsSuccessfully) {
  if (openFileDialog1.ShowDialog() != System.Windows.Forms.DialogResult.OK) {
    return;
  }

  OAuthUtility.PutAsync(

    "https://api-content.dropbox.com/1/files_put/auto",
    new HttpParameterCollection {
      {
        "access_token",
        login.AccessToken.Value
      }, {
        "path",
        Path.Combine(this.CurrentPath, Path.GetFileName(openFileDialog1.FileName)).Replace("\\", "/")
      }, {
        "overwrite",
        "true"
      }, {
        "autorename",
        "true"
      }, {
        openFileDialog1.OpenFile()
      }
    },
    callback: UploadFile_Result);

}

//  UploadFile_Result method
private void UploadFile_Result(RequestResult result) {
  if (this.InvokeRequired) {
    this.Invoke(new Action < RequestResult > (UploadFile_Result), result);
    return;
  }

  if (result.StatusCode == 200) {
    MessageBox.Show("File Uploaded Successfully");
  }
}

Posted By -	Karan Gupta

Posted On -	Saturday, May 9, 2015

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