TDBGrid  Checkbox column allowing only one record to be checked
lazarus / 16-Databases

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RedOctober · 2019-12-22 22:02

Platform:  FPC 3.0.4  Lazarus 1.8.4, OS:  Windows Server 2016

Goal:  In a TDBGrid that is displaying data from a Firebird 3x table
in the rows, I want each row to have a check box as the first column. 
I want all check boxes to be unchecked to start with, and then I want
the user to be able to check many, one or none, of the check boxes.

Progress:  I have successfully made a CheckBox column, the user can
put a check in the check box of a cell

Snag:  No matter how I work this, only one check box can be checked at
a time.  I can check the first check box, but when I check another
check box, all other check boxes, including the one I just checked,
reverts to either null (grayed with check) or is unchecked.   I want
my user to be able to check multiple check boxes (one in each row). 
How is this accomplished?  Is there a setting I am missing here?

~~~~~~~~~~~~~~
Tried: 
  Making the check box column a calculated field.  (same unwanted
behavior)
  Making a "virtual" field in the SQL that fetches the data  (same
unwanted behavior)

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valdir.marcos · 2019-12-23 18:24

Quote from: RedOctober on December 22, 2019, 11:02:48 pmPlatform:  FPC
3.0.4  Lazarus 1.8.4, OS:  Windows Server 2016

Goal:  In a TDBGrid that is displaying data from a Firebird 3x table
in the rows, I want each row to have a check box as the first column. 
I want all check boxes to be unchecked to start with, and then I want
the user to be able to check many, one or none, of the check boxes.

Progress:  I have successfully made a CheckBox column, the user can
put a check in the check box of a cell

Snag:  No matter how I work this, only one check box can be checked at
a time.  I can check the first check box, but when I check another
check box, all other check boxes, including the one I just checked,
reverts to either null (grayed with check) or is unchecked.   I want
my user to be able to check multiple check boxes (one in each row). 
How is this accomplished?  Is there a setting I am missing here?

~~~~~~~~~~~~~~
Tried: 
  Making the check box column a calculated field.  (same unwanted
behavior)
  Making a "virtual" field in the SQL that fetches the data  (same
unwanted behavior)Are using the proprieties "ValueChecked" and
"ValueUnchecked" on the Lazarus DBGrid field information?

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RedOctober · 2019-12-23 23:30

I found the answer at:  

https://wiki.freepascal.org/Grids_Reference_Page#Selecting_Records_in_
a_DBGrid_using_checkboxes

Scroll way down toward the bottom, section title:  "Selecting Records
in a DBGrid using checkboxes"