Passing UISearchBar Values To Another ViewController in MonoTouch

If you’re migrating your skills from web to mobile development it’s really easy to think in terms of passing user defined values from page to page when entering into a mobile environment. UIViewControllers aren’t web pages though, in the UIViewController world the ViewController is an object so no need to pass anything.

Here’s a UISearchBar that I’m using in an App, it’s in a ViewController (HomeScreen) and I want to get the value entered from HomeScreen to another ViewController (SearchResults) so that an API call can be made with the value.

View Controller with UISearchBar — HomeScreen UIViewController

I created a property on the HomeScreen ViewController outside of all the methods to support my needs:

// Holds the search criteria so SearchResultsViewController can access it.
public static string searchCriteria;

I populate the searchCriteria property in the SearchButtonClick event:

this.txtSearch.SearchButtonClicked += (sender, e) =>
{
searchCriteria = string.Empty;

// Populate the Search Criteria Property so it can be accessed from another view controller
searchCriteria = txtSearch.Text;

txtSearch.Text = string.Empty;

if (this._searchResultsViewController == null) {
this._searchResultsViewController = new searchResults ();
}

// Show the SearchResults ViewController
this.NavigationController.PushViewController (this._searchResultsViewController, true);
} ;

Then in the SearchResults ViewController the property can be accessed once the ViewController is loaded:

public override void ViewDidLoad ()
{
base.ViewDidLoad ();

string retrievedSearchCriteria = string.Empty;

// Access the Home Screen ViewController to get the Search Criteria
retrievedSearchCriteria = HomeScreen.searchCriteria;

// Use the value to search with… do stuff
}

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