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opening_20a_20file_20by_20dropping_20or_20clicking
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opening_20a_20file_20by_20dropping_20or_20clicking [2018/03/31 13:19] 127.0.0.1 external edit |
opening_20a_20file_20by_20dropping_20or_20clicking [2018/04/15 10:49] richardrussell Added syntax highlighting |
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| =====Opening a file by dropping or clicking===== | =====Opening a file by dropping or clicking===== | ||
| - | //by Richard Russell, October 2007//\\ \\ In Windows, some common ways of opening a file (for example a **document** or **image** file) are as follows:\\ | + | //by Richard Russell, October 2007//\\ \\ In Windows, some common ways of opening a file (for example a **document** or **image** file) are as follows: |
| * **Drag-and-drop** the file onto the icon of the application you want to open it. | * **Drag-and-drop** the file onto the icon of the application you want to open it. | ||
| Line 7: | Line 7: | ||
| * **Right-click** on the file's icon and select **Send To** from the menu. | * **Right-click** on the file's icon and select **Send To** from the menu. | ||
| * **Double-click** on the file's icon (it will be opened by the default viewer for that file type). | * **Double-click** on the file's icon (it will be opened by the default viewer for that file type). | ||
| - | \\ You may want your own BBC BASIC program to be able to open a file in one of these ways. That is easily achieved because in each case what happens is that the selected application is executed with the //path and name to the selected file// in the command line. So all you need to do in your program is extract the contents of the **@cmd$** system variable and use that as the path/name of the file to be opened.\\ \\ There is just one minor complication. If the path or name of the file contains spaces, Windows encloses the entire **@cmd$** string in quotation marks ("). Your program must remove those before the the path/filename is suitable for use.\\ \\ Here is a very simple program which displays a BMP file:\\ \\ | + | |
| + | You may want your own BBC BASIC program to be able to open a file in one of these ways. That is easily achieved because in each case what happens is that the selected application is executed with the //path and name to the selected file// in the command line. So all you need to do in your program is extract the contents of the **@cmd$** system variable and use that as the path/name of the file to be opened.\\ \\ There is just one minor complication. If the path or name of the file contains spaces, Windows encloses the entire **@cmd$** string in quotation marks ("). Your program must remove those before the the path/filename is suitable for use.\\ \\ Here is a very simple program which displays a BMP file: | ||
| + | |||
| + | <code bb4w> | ||
| bmpfile$ = @cmd$ | bmpfile$ = @cmd$ | ||
| IF ASC(bmpfile$)=34 bmpfile$=EVAL(bmpfile$) | IF ASC(bmpfile$)=34 bmpfile$=EVAL(bmpfile$) | ||
| OSCLI "DISPLAY """+bmpfile$+"""" | OSCLI "DISPLAY """+bmpfile$+"""" | ||
| - | The first line copies the contents of **@cmd$** (since you must not attempt to modify the contents of that variable). The second line examines the path/filename and if it is enclosed in quotation marks they are stripped off. The third line displays the image; note the addition of quotation marks. It may seem strange to strip off the quotes and then put them back again, but that ensures that the contents of **bmpfile$** are in a suitable form whenever a valid path/filename is needed (for example in an **OPENIN** function).\\ \\ Of course this only works when you have 'compiled' your program to a standalone executable, since only then can your program be executed by Windows in this way. When testing your program in the Interactive Development Environment **@cmd$** will contain an empty string. You may therefore wish to add to your program so that in these circumstances it requests the filename, for example:\\ \\ | + | </code> |
| + | |||
| + | The first line copies the contents of **@cmd$** (since you must not attempt to modify the contents of that variable). The second line examines the path/filename and if it is enclosed in quotation marks they are stripped off. The third line displays the image; note the addition of quotation marks. It may seem strange to strip off the quotes and then put them back again, but that ensures that the contents of **bmpfile$** are in a suitable form whenever a valid path/filename is needed (for example in an **OPENIN** function).\\ \\ Of course this only works when you have 'compiled' your program to a standalone executable, since only then can your program be executed by Windows in this way. When testing your program in the Interactive Development Environment **@cmd$** will contain an empty string. You may therefore wish to add to your program so that in these circumstances it requests the filename, for example: | ||
| + | |||
| + | <code bb4w> | ||
| bmpfile$ = @cmd$ | bmpfile$ = @cmd$ | ||
| IF ASC(bmpfile$)=34 bmpfile$=EVAL(bmpfile$) | IF ASC(bmpfile$)=34 bmpfile$=EVAL(bmpfile$) | ||
| IF bmpfile$ = "" THEN bmpfile$ = FNrequestfile | IF bmpfile$ = "" THEN bmpfile$ = FNrequestfile | ||
| OSCLI "DISPLAY """+bmpfile$+"""" | OSCLI "DISPLAY """+bmpfile$+"""" | ||
| + | </code> | ||
| + | |||
| Here **FNrequestfile** is assumed to prompt the user to enter (or select) a filename, perhaps by means of an [[http://www.bbcbasic.co.uk/bbcwin/manual/bbcwin5.html#input|INPUT]] statement or by using the Windows [[http://www.bbcbasic.co.uk/bbcwin/manual/bbcwine.html#opensave|GetOpenFileName]] dialogue.\\ \\ To add your compiled application to the **Send To** list you need to place a shortcut there as follows:\\ | Here **FNrequestfile** is assumed to prompt the user to enter (or select) a filename, perhaps by means of an [[http://www.bbcbasic.co.uk/bbcwin/manual/bbcwin5.html#input|INPUT]] statement or by using the Windows [[http://www.bbcbasic.co.uk/bbcwin/manual/bbcwine.html#opensave|GetOpenFileName]] dialogue.\\ \\ To add your compiled application to the **Send To** list you need to place a shortcut there as follows:\\ | ||
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| * Right-drag your application into the SendTo folder, and select 'Create shortcut here'. | * Right-drag your application into the SendTo folder, and select 'Create shortcut here'. | ||
| * Select File... New and then click Shortcut. | * Select File... New and then click Shortcut. | ||
| - | \\ To make your application the default viewer for a specific file type you will need to edit the file **associations**. You can do that as follows:\\ | + | |
| + | To make your application the default viewer for a specific file type you will need to edit the file **associations**. You can do that as follows:\\ | ||
| - Open **My Computer** or **Windows Explorer**. | - Open **My Computer** or **Windows Explorer**. | ||
opening_20a_20file_20by_20dropping_20or_20clicking.txt · Last modified: 2018/04/15 10:49 by richardrussell
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