| Subject | Re: beforeGetValue event |
| From | Mervyn Bick <invalid@invalid.invalid> |
| Date | Thu, 14 Dec 2017 19:51:07 +0200 |
| Newsgroups | dbase.getting-started |
| Attachment(s) | whatevertable.wfm |
On 2017-12-14 5:46 PM, Al W wrote: > Hi Mervyn Bick > I have attempted to follow your leadership and used the following 4 steps derived from your text and creating a whatever table.. > 1. If you are using the calculated field in a form a slightly different approach is appropriate. In a form a good place to create a calculated field is in a query's onOpen event handler. > 2. After you have placed a table on the form use the arrow button of the combobox on the Inspector to display the list of objects. Select the query object. dBASE names queries with the tablename plus an ordinal number. tablename1, tablename2, etc although you are free to change object names to suit yourself. > 3. Select the "event" tab and click on "onOpen" to select it. Click on the "spanner" button and dBASE will open the sourcecode editor with an empty onOpen event handler. Add the code, close the sourcecode editor and save the form. > 4. If TOTAL is in the table but not populated then > function WHATEVERTABLE1_onOpen() > this.rowset.fields["total"].beforeGetValue := {||this.parent["wage > rate1"].value + this.parent["fringes1"].value} > return > > After implementing my version of these steps I still don’t get it to work. The attached copy of the file from the Source Editor/Designer shows where I am now. > Hope you can still help me > Thanks > AL W "Whatever" and "whatevertable" are placeholders as I didn't know what the actual names were. The principles apply to any table. I've created a little table which I've named whatevertable.dbf mainly to match the name of your form. This helps me keep example forms and tables together on my computer. Having spaces in field names is allowable but at times they need special handling. As I needed a table with which to test your code I created a new table. In this I've named the field wage_rate. By placing the code in the form's header section it will be created in the same folder as the form. Although dBASE and Windows will allow it, you shouldn't place code or tables in C:\Users\MyPC\AppData\Local\dBASE\Plus11\Bin. Rather create a new folder for your dBASE work. Perhaps c:\dBase While you are still learning how to use dBASE it simplifies things to have code and data in the same folder. Once you start with larger applications where you have many data files it is, however, preferable to keep code and data in separate folders. Don't worry if the constructor code for the query in the attached form looks "different". This is the format used by older versions of dBASE. Because the dBASE designer now uses the full path for tables in a query I have a little program that strips the path out and, at the same time, changes the code so that the code will also run on older versions of dBASE. There were a couple of reasons why your form wouldn't run. You hadn't created the new field in the query's onOpen event handler. You also hadn't assigned the event handler to the event in the query's constructor code. A revised version of your form is attached. Mervyn. | |
if file('whatevertable.dbf') drop table whatevertable endif if not file('whatevertable.dbf') create table whatevertable (id autoinc,trade character(15),wage_rate numeric(10,2),; fringes numeric(10,2)) insert into whatevertable (trade,wage_rate,fringes) values ("Electrician",120.00,12.00) insert into whatevertable (trade,wage_rate,fringes) values ("Plumber",110.00,11.00) insert into whatevertable (trade,wage_rate,fringes) values ("Brick layer",90.00,9.00) insert into whatevertable (trade,wage_rate,fringes) values ("Plasterer",90.00,9.00) endif ** END HEADER -- do not remove this line // // Generated on 14/12/2017 // parameter bModal local f f = new WHATEVERTABLEForm() if (bModal) f.mdi = false // ensure not MDI f.readModal() else f.open() endif class WHATEVERTABLEForm of FORM with (this) onOpen = class::FORM_ONOPEN colorNormal = "Aliceblue" height = 25.4545 left = 0.0 top = 0.0 width = 192.2857 text = "Whatevertable" scrollBar = 2 // Auto endwith this.WHATEVERTABLE1 = new QUERY() this.WHATEVERTABLE1.parent = this with (this.WHATEVERTABLE1) onOpen = class::WHATEVERTABLE1_onOpen left = 34.0 width = 12.0 height = 1.0 sql = 'select * from "whatevertable.dbf"' active = true endwith this.TEXTTRADE1 = new TEXT(this) with (this.TEXTTRADE1) height = 1.0 left = 80.0 top = 8.0 width = 5.7143 wrap = false colorNormal = "BtnText/Aliceblue" alignVertical = 2 // Bottom fontName = "Arial Narrow" fontSize = 11.0 fontBold = true fontItalic = true text = "Trade" endwith this.ENTRYFIELDTRADE1 = new ENTRYFIELD(this) with (this.ENTRYFIELDTRADE1) dataLink = form.whatevertable1.rowset.fields["trade"] height = 1.0 left = 80.0 top = 9.0 width = 32.0 fontName = "Arial Narrow" fontSize = 12.0 endwith this.ENTRYFIELDWAGE_RATE1 = new ENTRYFIELD(this) with (this.ENTRYFIELDWAGE_RATE1) dataLink = form.whatevertable1.rowset.fields["wage_rate"] height = 1.0 left = 93.0 top = 10.5 width = 8.0 fontName = "Arial Narrow" fontSize = 12.0 endwith this.ENTRYFIELDFRINGES1 = new ENTRYFIELD(this) with (this.ENTRYFIELDFRINGES1) dataLink = form.whatevertable1.rowset.fields["fringes"] height = 1.0 left = 93.0 top = 11.5 width = 8.0 fontName = "Arial Narrow" fontSize = 12.0 endwith this.ENTRYFIELDTOTAL1 = new ENTRYFIELD(this) with (this.ENTRYFIELDTOTAL1) dataLink = form.whatevertable1.rowset.fields["total"] height = 1.0 left = 93.0 top = 12.5 width = 8.0 fontName = "Arial Narrow" fontSize = 12.0 endwith this.TITLE1 = new TEXT(this) with (this.TITLE1) height = 2.0 left = 1.0 top = 0.0 width = 21.1429 variableHeight = true colorNormal = "Black/Aliceblue" fontSize = 14.0 fontBold = true fontItalic = true text = "Whatevertable" endwith this.rowset = this.whatevertable1.rowset function form_onOpen() return function WHATEVERTABLE1_onOpen() c = new field() c.fieldName := "Total" this.rowset.fields.add(c) this.rowset.fields["total"].beforeGetValue := {||this.parent["wage_rate"].value + this.parent["fringes"].value} return endclass | |