I have a "MainForm" and a "GraphicsForm". Clicking "New" on the main form, a "GraphicsForm" will be created. The problem is that when I create multiple "GraphicsForm", and I want to save the content of one of the "GraphicsForm", I need to clicking "Save" on the "MainForm" and the program will write the content to a file, I don't know how to pass the content of this "GraphicsForm" to "MainForm" for storage.

If I have anything that is not clearly described, I hope you can point it out and I will edit my issue ASAP.

CodePudding user response：

I'm sure this has been answered before but basically, you pass in an instance of the 'data storage' to the new form.

interface ISaveForm
{
    void Save();
}

class MainForm
{
    private DataStorage _dataStorage;
    private ICollection<ISaveForm> _forms = new List<ISaveForm>();

    public void OnNew()
    {
        var subForm = new GraphicsForm(_dataStorage);
        subForm.Show();
        _forms.Add(subForm);
    }
    public void OnSave()
    {
       foreach(var form in _forms)
       {
         form.Save();
       }
    }
}
class GraphicsForm : Form,ISaveForm
{
    private DataStorage _dataStorage;

    public GraphicsForm(DataStorage dataStorage)
    {
        _dataStorage = dataStorage;
    }
    public void Save()
    {
    }
}

CodePudding user response：

Because MainForm is a MDI form, it is easy to use ActiveMdiChild to get the active child form.

class MainForm : Form
{
    public void OnSaveButtonClick(object sender, EventArgs e)
    {
        if(ActiveMdiChild is GraphicsForm g)
            Save(g);
    }
}