Combobox
in [CSharp]
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From: Michel Racicot on 23 Apr 2010 19:42 Far more easy to understand ;) I've added a string property (named "TokenType" to the custom combobox... dropped the customcombo on a form and set the new property in the property inspector in design time. But if I try to access the value in the constructor of the ComboBox (to load its value), it's not set! The string is empty... So I can't use it to load the combo correctly. "Family Tree Mike" <FamilyTreeMike(a)ThisOldHouse.com> wrote in message news:OuUx7vz4KHA.3880(a)TK2MSFTNGP04.phx.gbl... > On 4/23/2010 6:10 PM, Michel Racicot wrote: >> The problem is that my custom property isn't set yet in the >> constructor.... I don't understand why... >> > > Can you explain what that means? Do you mean that you need a property to > be set "within" the constructor, so that you need a non-parameterless (if > that is a word) constructor, something like below? I don't think this is > possible for a control given that a user may drop it onto a form. > > public class MyComboBox : ComboBox > { > public string ConnectionString {get; set;} > public MyComboBox (string connectionstring) > { > ConnectionString = connectionstring; > // open a dataset, for example... > } > } > > -- > Mike
From: Michel Racicot on 23 Apr 2010 19:46 Obviously, from the code in the designer of the form, the constructors of child controls are called before setting the properties... That makes sense. But I need an event that will be called after the properties are set... like a custom "OnLoad" event. "Family Tree Mike" <FamilyTreeMike(a)ThisOldHouse.com> wrote in message news:OuUx7vz4KHA.3880(a)TK2MSFTNGP04.phx.gbl... > On 4/23/2010 6:10 PM, Michel Racicot wrote: >> The problem is that my custom property isn't set yet in the >> constructor.... I don't understand why... >> > > Can you explain what that means? Do you mean that you need a property to > be set "within" the constructor, so that you need a non-parameterless (if > that is a word) constructor, something like below? I don't think this is > possible for a control given that a user may drop it onto a form. > > public class MyComboBox : ComboBox > { > public string ConnectionString {get; set;} > public MyComboBox (string connectionstring) > { > ConnectionString = connectionstring; > // open a dataset, for example... > } > } > > -- > Mike
From: Michel Racicot on 23 Apr 2010 19:49 And the Layout event seems to be called too often to my taste. "Michel Racicot" <mracicot(a)hotmail.com> wrote in message news:uJx3w6z4KHA.1932(a)TK2MSFTNGP05.phx.gbl... > Far more easy to understand ;) > > I've added a string property (named "TokenType" to the custom combobox... > dropped the customcombo on a form and set the new property in the property > inspector in design time. > > But if I try to access the value in the constructor of the ComboBox (to > load its value), it's not set! The string is empty... So I can't use it > to load the combo correctly. > > "Family Tree Mike" <FamilyTreeMike(a)ThisOldHouse.com> wrote in message > news:OuUx7vz4KHA.3880(a)TK2MSFTNGP04.phx.gbl... >> On 4/23/2010 6:10 PM, Michel Racicot wrote: >>> The problem is that my custom property isn't set yet in the >>> constructor.... I don't understand why... >>> >> >> Can you explain what that means? Do you mean that you need a property to >> be set "within" the constructor, so that you need a non-parameterless (if >> that is a word) constructor, something like below? I don't think this is >> possible for a control given that a user may drop it onto a form. >> >> public class MyComboBox : ComboBox >> { >> public string ConnectionString {get; set;} >> public MyComboBox (string connectionstring) >> { >> ConnectionString = connectionstring; >> // open a dataset, for example... >> } >> } >> >> -- >> Mike >
From: Family Tree Mike on 23 Apr 2010 20:30
On 4/23/2010 7:46 PM, Michel Racicot wrote: > Obviously, from the code in the designer of the form, the constructors > of child controls are called before setting the properties... That makes > sense. > > But I need an event that will be called after the properties are set... > like a custom "OnLoad" event. > Assuming you want to fill the combobox items when the property changes, in the designer or at runtime, then I would code it like this: public class MyComboBox : ComboBox { string _TokenType; public string TokenType { get { return _TokenType; } set { _TokenType = value; Items.Clear(); Items.Add(TokenType); SelectedIndex = 0; } } } -- Mike |