How to work with the snap environment

In this topic

• Working with the snap environment
• Snap agents
• Snapping in z-dimension
• Snap point method

Working with the snap environment

public void SnapEnvirSettings(IEngineEditor editor)
{
    //Get the snap environment from the editor.
    IEngineSnapEnvironment snapEnvironment=editor as IEngineSnapEnvironment;

    //Ensure there is a snap agent turned on in the snap environment.
    if (snapEnvironment.SnapAgentCount == 0)
    {
        System.Windows.Forms.MessageBox.Show(
            "You need to turn on at least one snapping agent!!!");
        return ;
    }

    //Code to display the snap tolerance in a message box. 
    double tolerance=snapEnvironment.SnapTolerance;
    System.Windows.Forms.MessageBox.Show(Convert.ToString(tolerance));

    //Set the snap tolerance.
    snapEnvironment.SnapToleranceUnits =
        esriEngineSnapToleranceUnits.esriEngineSnapToleranceMapUnits;
    snapEnvironment.SnapTolerance=15;

    //Turn on snap tips.
    ((IEngineEditProperties2)editor).SnapTips=true;
}

Public Sub SnapEnvirSettings(ByVal editor As IEngineEditor)
    'Get the snap environment from the editor.
    Dim snapEnvironment As IEngineSnapEnvironment=editor As IEngineSnapEnvironment
    
    'Ensure there is a snap agent turned on in the snap environment.
    If snapEnvironment.SnapAgentCount=0 Then
        System.Windows.Forms.MessageBox.Show("You need to turn on at least one snapping agent!!!")
        Return
    End If
    
    'Code to display the snap tolerance in a message box.
    Dim tolerance As Double=snapEnvironment.SnapTolerance
    System.Windows.Forms.MessageBox.Show(Convert.ToString(tolerance))
    
    'Set the snap tolerance.
    snapEnvironment.SnapToleranceUnits=esriEngineSnapToleranceUnits.esriEngineSnapToleranceMapUnits
    snapEnvironment.SnapTolerance=15
    
    'Turn on snap tips.
    ((IEngineEditProperties2)editor).SnapTips=True
End Sub

private bool CheckIsAnySnapAgentSelected(IEngineSnapEnvironment snapEnvironment)
{
    int snapAgentCount=snapEnvironment.SnapAgentCount;
    int checkedFeatureSnapAgentCount=0;
    int featureSnapAgentCount=0;

    //Loop through all registered snap agents in the snap environment. Count feature snap agents,
    //checked feature snap agents, and nonfeature snap agents.
    for (int i=0; i < snapAgentCount; i++)
    {
        IEngineSnapAgent currentSnapAgent=snapEnvironment.get_SnapAgent(i);
        if (currentSnapAgent is IEngineFeatureSnapAgent)
        {
            IEngineFeatureSnapAgent featureSnapAgent=currentSnapAgent as
                IEngineFeatureSnapAgent;
            featureSnapAgentCount++;

            //Determine if the feature snap agent is checked.
            if (featureSnapAgent.HitType !=
                esriGeometryHitPartType.esriGeometryPartNone)
            {
                checkedFeatureSnapAgentCount++;
            }
        }
    }
    if (checkedFeatureSnapAgentCount > 0 || snapAgentCount > featureSnapAgentCount)
    {
        return true;
    }
    else
    {
        return false;
    }
}

Private Function CheckIsAnySnapAgentSelected(ByVal snapEnvironment As IEngineSnapEnvironment) As Boolean
    Dim snapAgentCount As Integer=snapEnvironment.SnapAgentCount
    Dim checkedFeatureSnapAgentCount As Integer=0
    Dim featureSnapAgentCount As Integer=0
    
    'Loop through all registered snap agents in the snap environment. Count feature snap agents,
    'checked feature snap agents, and nonfeature snap agents.
    Dim i As Integer
    For i=0 To snapAgentCount - 1 Step i + 1
        Dim currentSnapAgent As IEngineSnapAgent=snapEnvironment.get_SnapAgent(i)
        If TypeOf currentSnapAgent Is IEngineFeatureSnapAgent Then
            Dim featureSnapAgent As IEngineFeatureSnapAgent=currentSnapAgent As IEngineFeatureSnapAgent
            featureSnapAgentCount=featureSnapAgentCount + 1
            
            'Determine if the feature snap agent is checked.
            If featureSnapAgent.HitType <> esriGeomeTryHitPartType.esriGeomeTryPartNone Then
                checkedFeatureSnapAgentCount=checkedFeatureSnapAgentCount + 1
            End If
        End If
    Next
    If checkedFeatureSnapAgentCount > 0 Or snapAgentCount > featureSnapAgentCount Then
        Return True
    Else
        Return False
    End If
End Function

Snap agents

public void AddNewSnapAgent()
{
    IEngineEditor editor=new EngineEditorClass();
    IEngineEditLayers editLayers=editor as IEngineEditLayers;
    IEngineSnapEnvironment snapEnvironment=editor as IEngineSnapEnvironment;

    //Check that the user is editing; otherwise, there will be no snap agent loaded.
    if (editLayers.TargetLayer == null)
    {
        System.Windows.Forms.MessageBox.Show("Please start an edit session");
        return ;
    }

    //Clear all existing snap agents.
    snapEnvironment.ClearSnapAgents();

    //Create a feature snap agent.
    IEngineFeatureSnapAgent featureSnapAgent=new EngineFeatureSnap();
    IFeatureClass layerFeatureClass=editLayers.TargetLayer.FeatureClass;
    featureSnapAgent.FeatureClass=layerFeatureClass;
    featureSnapAgent.HitType=esriGeometryHitPartType.esriGeometryPartBoundary;

    //Activate only the snap agent for the target layer.
    snapEnvironment.AddSnapAgent(featureSnapAgent);
}

Public Sub AddNewSnapAgent()
    Dim editor As IEngineEditor=New EngineEditorClass()
    Dim editLayers As IEngineEditLayers=editor As IEngineEditLayers
    Dim snapEnvironment As IEngineSnapEnvironment=editor As IEngineSnapEnvironment
    
    'Check that the user is editing; otherwise, there will be no snap agent loaded.
    If editLayers.TargetLayer Is Nothing Then
        System.Windows.Forms.MessageBox.Show("Please start an edit session")
        Return
    End If
    
    'Clear all existing snap agents.
    snapEnvironment.ClearSnapAgents()
    
    'Create a feature snap agent.
    Dim featureSnapAgent As IEngineFeatureSnapAgent=New EngineFeatureSnap()
    Dim layerFeatureClass As IFeatureClass=editLayers.TargetLayer.FeatureClass
    featureSnapAgent.FeatureClass=layerFeatureClass
    featureSnapAgent.HitType=esriGeomeTryHitPartType.esriGeomeTryPartBoundary
    
    'Activate only the snap agent for the target layer.
    snapEnvironment.AddSnapAgent(featureSnapAgent)
End Sub

Snapping in z-dimension

Snap point method

See Also: