Tag Archives: snippet
How to generate QR barcodes in C#
QR barcodes are machine-readable optical labels that contain certain information. Today we will be looking into how to generate QR codes with the use of the ZXing.Net library.
First you will need to download the ZXing.Net library from zxingnet.codeplex.com. Extract the contents of the file you have downloaded and reference the library that fits your needs in your project.
Using the example code below you will now be able to create your own QR codes.
1 2 3 4 5 6 7 8 9 10 | public Bitmap GenerateQR(int width, int height, string text) { var bw = new ZXing.BarcodeWriter(); var encOptions = new ZXing.Common.EncodingOptions() { Width = width, Height = height, Margin = 0 }; bw.Options = encOptions; bw.Format = ZXing.BarcodeFormat.QR_CODE; var result = new Bitmap(bw.Write(text)); return result; } |
Example: Calling the following method will return a Bitmap object which you can save using the Bitmap’s Bitmap.Save() method or simply display it within your application.
1 | GenerateQR(200, 200, "http://www.fluxbytes.com/csharp/generating-qr-barcode-in-c/"); |
Unzip files using Shell32 in C#
The .NET Framework didn’t have an easy way for developers to unzip files resulting to a lot of people having to use third party libraries to achieve that functionality. This was until the .NET Framework 4.5 was released which had a new class called ZipFile that simplified the process of unzipping files..
But since targeting the .NET Framework 4.5 might not be ideal in many cases, mainly because its adaptation rate is still fairly low I will demostrate another way to unzip .zip files with the use of Shell32.
Firstly you will need to reference in your project the COM library called Microsoft Shell Controls And Automation (Interop.Shell32.dll) in order to be able to access the Shell32 namespace.
The method below is a simple example that takes two parameters. The .zip file location and the folder destination where the files will be extracted to.
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 | public static void UnZip(string zipFile, string folderPath) { if (!File.Exists(zipFile)) throw new FileNotFoundException(); if (!Directory.Exists(folderPath)) Directory.CreateDirectory(folderPath); Shell32.Shell objShell = new Shell32.Shell(); Shell32.Folder destinationFolder = objShell.NameSpace(folderPath); Shell32.Folder sourceFile = objShell.NameSpace(zipFile); foreach (var file in sourceFile.Items()) { destinationFolder.CopyHere(file, 4 | 16); } } |
The usage is fairly simple:
1 | UnZip(@"C:\myzipfile.zip", @"C:\my destination folder"); |
Creating and connecting to a Microsoft Access Database programmatically in C#
The following example aims to get you a bit more familiar as to how to create and connect to a Microsoft Access database programmatically while being able to add any type of tables you want as well are inserting and retrieving data from it.
Firstly we will need to reference two libraries in our project. Microsoft ActiveX Data Objects 2.0 Library (Interop.ADODB.dll) which we will use to ensure that the connection to the database is closed after we are done creating it, and Microsoft ADO Ext. 2.8 for DDL and Security (Interop.ADOX.dll) which is needed to be able to access the classes that are required to create our database.
After you have finished adding those two references to your project you can use the code sample below to create the database file programmatically. Feel free to modify the code to suit your needs. Also please note that setting your project to Any CPU build will cause exceptions to be thrown when creating the database.
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 | public static void CreateAccessDatabase() { string connectionString = string.Format("Provider={0}; Data Source={1}; Jet OLEDB:Engine Type={2}", "Microsoft.Jet.OLEDB.4.0", "mydb.mdb", 5); ADOX.CatalogClass catalog = new ADOX.CatalogClass(); catalog.Create(connectionString); ADOX.Table table = new ADOX.Table(); table.Name = "Users"; // Table name // Column 1 (id) ADOX.ColumnClass idCol = new ADOX.ColumnClass(); idCol.Name = "Id"; // The name of the column idCol.ParentCatalog = catalog; idCol.Type = ADOX.DataTypeEnum.adInteger; // Indicates a four byte signed integer. idCol.Properties["AutoIncrement"].Value = true; // Enable the auto increment property for this column. // Column 2 (Name) ADOX.ColumnClass nameCol = new ADOX.ColumnClass(); nameCol.Name = "Name"; // The name of the column nameCol.ParentCatalog = catalog; nameCol.Type = ADOX.DataTypeEnum.adVarWChar; // Indicates a string value type. nameCol.DefinedSize = 60; // 60 characters max. // Column 3 (Surname) ADOX.ColumnClass surnameCol = new ADOX.ColumnClass(); surnameCol.Name = "Surname"; // The name of the column surnameCol.ParentCatalog = catalog; surnameCol.Type = ADOX.DataTypeEnum.adVarWChar; // Indicates a string value type. surnameCol.DefinedSize = 60; // 60 characters max. table.Columns.Append(idCol); // Add the Id column to the table. table.Columns.Append(nameCol); // Add the Name column to the table. table.Columns.Append(surnameCol); // Add the Surname column to the table. catalog.Tables.Append(table); // Add the table to our database. // Close the connection to the database after we are done creating it and adding the table to it. ADODB.Connection con = (ADODB.Connection)catalog.ActiveConnection; if (con != null && con.State != 0) con.Close(); } |
Monitor for clipboard changes using AddClipboardFormatListener
Microsoft has added a new windows function to help monitor when the data in the clipboard has been changed. The new function is called AddClipboardFormatListener but sadly it is only available for Windows Vista and higher. If you are looking for a method that will work for earlier versions of Windows take a look at Monitor clipboard in C#.
The principle is the same with the older method. We need to add our window to the clipboard format listener list so it can receive the WM_CLIPBOARDUPDATE message.
In order to do that we need to pinvoke the AddClipboardFormatListener and RemoveClipboardFormatListener.
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 | /// <summary> /// Places the given window in the system-maintained clipboard format listener list. /// </summary> [DllImport("user32.dll", SetLastError = true)] [return: MarshalAs(UnmanagedType.Bool)] static extern bool AddClipboardFormatListener(IntPtr hwnd); /// <summary> /// Removes the given window from the system-maintained clipboard format listener list. /// </summary> [DllImport("user32.dll", SetLastError = true)] [return: MarshalAs(UnmanagedType.Bool)] static extern bool RemoveClipboardFormatListener(IntPtr hwnd); /// <summary> /// Sent when the contents of the clipboard have changed. /// </summary> private const int WM_CLIPBOARDUPDATE = 0x031D; |
Posted in C#.
Tagged AddClipboardFormatListener, C#, csharp, RemoveClipboardFormatListener, snippet, winforms, WM_CLIPBOARDUPDATE
How to display a progressbar in taskbar in C#
You might have noticed that programs display a progress bar in the taskbar a lot of times. This allows users to see the progression of the task even if the application is minimized by simply looking at the taskbar. Today I will be showing you a way to achieve that functionality so you can use it in your projects.
First you will need to download Windows API Code Pack for Microsoft .NET Framework. Extract the contents of the file and search for Microsoft.WindowsAPICodePack.Shell.dll which is located under the binaries folder.
Add Microsoft.WindowsAPICodePack.Shell.dll as a reference to your project. This will allow you to use the namespaces which are required in order to display the progress bar.
The code below is an example on how you can implement the feature.
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 | if (Microsoft.WindowsAPICodePack.Taskbar.TaskbarManager.IsPlatformSupported) { int maxProgressbarValue = 100; var taskbarInstance = Microsoft.WindowsAPICodePack.Taskbar.TaskbarManager.Instance; taskbarInstance.SetProgressState(Microsoft.WindowsAPICodePack.Taskbar.TaskbarProgressBarState.Normal); for (int i = 0; i < maxProgressbarValue; i++) { taskbarInstance.SetProgressValue(i, maxProgressbarValue); Thread.Sleep(50); } taskbarInstance.SetProgressState(Microsoft.WindowsAPICodePack.Taskbar.TaskbarProgressBarState.NoProgress); } else { // Platform does not support the feature. } |
