Searching in Nodes

Introduction

When searching in nodes, the search conditions are specified by a predicate delegate. During the search, the xamNetworkNode™ control enumerates all nodes and calls the predicate delegate on each node. A network node is considered a match and returned in the search results if its underlying data fulfills the conditions of the predicate delegate. The matching results are presented as a collection of NetworkNodeNode objects.

Implementing Searching in Nodes

There are two implementation approaches based on how the predicate delegate is defined. Each of them is covered in an individual sub-section below.

Using a Standard Predicate Delegate

When using a standardly defined predicate delegate, you first create the predicate delegate (the search condition), and then use it to perform the search.

Create the predicate delegate.

Define a predicate delegate search condition.

The predicate delegate is a method that accepts a generic parameter and returns a Boolean value.

The following method receives a NodeModel object and compares its Label to a string.

In Visual Basic:

Private _searchText As String = "some text"
Private Function SearchCondition(node As NodeModel) As Boolean
    Dim nodeLabel As String = node.Label.ToLower()
    'Compare the label to a string.
    Return nodeLabel.Contains(_searchText)
End Function

In C#:

private string _searchText = "some text";
private bool SearchCondition(NodeModel node)
{
    string nodeLabel = node.Label.ToLower();
    //Compare the label to a string.
    return nodeLabel.Contains(_searchText);
}

Encapsulate the Search Condition method.

Create a Predicate<T> object, which will encapsulate the SearchCondition method created in Step 1. The predicate object will be passed as a parameter to the Search method of Network Node:

In Visual Basic:
```
Dim searchCondition As New _
    Predicate(Of NodeModel)(AddressOf SearchCondition)
```
In C#:
```
Predicate searchCondition = new Predicate(SearchCondition);
```

Perform the search.

Using a Lambda Expression

This is a "shortcut" approach: it uses a lambda expression to define the predicate delegate directly in the Search method.