Pass Parameter to UserControl

[eb24]

I have a main form (frmMain) that displays a listbox (lboData) with values from a datasource. Upon a user double-clicking on a value from this list, another form, frmFeature, is displayed. This frmFeature contains a UserControl, ucFeature that is suppose to get the ID from the lboData from the frmMain.

This is what I have for frmMain:

private void lboData_DoubleClick(object sender, EventArgs e)
{
     string myID = lboData.SelectedValue.ToString();
     frmFeature frm = new frmFeature();
     frm.UC.LoadData(myID);
     frm.ShowDialog();
}

This is what I have for frmFeature:

public frmFeature()
{
     InitializeComponent();
}
public ucFeature UC
{
     get 
     {
          return ucFeature1;
     }
}

This is what I have for ucFeature:

public partial class ucFeature: UserControl
{
     public ucFeature(string myID)
     {
          string myID = null;
          InitializeComponent();
          DisplayID(myID);

     }
     public void DisplayID(string myID)
     {
          lblID.Text = myID.ToString();
     }
...

When I run the code, I get the following: Message="Object reference not set to an instance of an object.". Any and all assistance will be greatly appreciated.

 

[misterstick]

     public ucFeature(string myID)
     {
          [COLOR=red]// explicitly setting myId to null; why?[/color]
          // did you mean this to be a member variable?
          string myID = null;
          InitializeComponent();
          DisplayID(myID);

     }
     public void DisplayID(string myID)
     {
          [COLOR=red]// why are you calling ToString() on a string?[/color]
          lblID.Text = myID.ToString();
     }

mr s. <

 

[jmeckley]

public ucFeature UC
{
     get { return ucFeature1; }
}

is ucFeature1 initialized in the designer (view or code)? if not this may fix the problem.

public ucFeature UC
{
     get { return new ucFeature("ID"); }
}

Jason Meckley
Programmer
Specialty Bakers, Inc.

 

[misterstick]

the code as provided will throw an error on [tt]lblID.Text = myID.ToString();[/tt] because myID is being set to null.

take out the line [[tt]string myID = null;[/tt] and it should run.

mr s. <

 

[eb24]

OK, I'm still a bit confused:

This is what I basically want (call-order):

frmMain --> frmFeature --> ucFeature

I want my ucFeature to get a parameter from frmMain so it can be used within my ucFeature. Maybe my initial code was a bit confusing. I added DisplayID just so I could see if it was being passed. Since then, I have deleted some code.

So, basically, I want the following line from frmMain:

frm.UC.LoadData(myID);

To be received by my UserControl, ucFeature:

public void LoadData(string myID)
{...}

Does this make better sense? Thank you!