WinForms主从细节的程序化绑定

Question

I've got a WinForms app with an Explorer style TreeView on the left. Selecting different nodes will display different UserControls composed of various other standard controls. All of the controls within the various UserControls are bound to a single DataSet. I have a ComboBox above the scope of the tree (to change between test and live settings) bound a master table, and as I have master-detail relationships setup between the tables, changing the ComboBox changes the current row for all child tables. So far, so good.

I've now added plugable sub-trees (picked up from separate DLLs), and each sub-tree uses it's own DataSet. The part I'm having trouble with is how to make the sub-trees link to the master table. I've replicated the master table within the sub-trees' DataSets (because the relations won't work between DataSets), but because the sub-trees don't have their own ComboBox, I'm unsure how to make the binding work. I guess I need a CurrencyManager for each sub-tree, and somehow link them to the ComboBox's change event, but how do I relate the sub-tree's UserControls to the CurrencyManager?

Answer 1

The piece I was missing was creating a BindingContext for the sub-tree...

bindingContext = new BindingContext();

...and then setting it on the sub-tree's UserControls:

public partial class MyUserControl : UserControl
{
    public MyUserControl(BindingContext bindingContext, DataSet dataSet)
    {
        this.BindingContext = bindingContext;
        InitializeComponent();
        myTextBox.DataBindings.Add("Text", dataSet, "Master.Master_Detail.DetailField");
    }
}

I didn't understand that the CurrencyManager doesn't need to be explicitly created to link with the DataSet. Setting the DataBindings is enough.

Keeping the two separate DataSets in step then just required a method like this:

public void MasterChanged(long masterID)
{
    var currencyManager = bindingContext[dataModel.DataSet, "Master"];
    var masterRows = masterTable.Rows;
    for (int position = 0; position < masterRows.Count; position++)
    {
        if (((long)masterRows[position]["ID"]) == masterID)
        {
            currencyManager.Position = position;
            break;
        }
    }
}