ProSnippets Arcade - Esri/arcgis-pro-sdk GitHub Wiki

Language:              C#  
Subject:               Arcade  
Contributor:           ArcGIS Pro SDK Team <[email protected]>  
Organization:          esri, http://www.esri.com  
Date:                  10/22/2024  
ArcGIS Pro:            3.4  
Visual Studio:         2022  
.NET Target Framework: .Net 8  

Basic Queries

Basic Query

//Consult https://github.com/Esri/arcade-expressions/ and
//https://developers.arcgis.com/arcade/ for more examples
//and arcade reference

QueuedTask.Run(() =>
{
  //construct an expression
  var query = @"Count($layer)";//count of features in "layer"

  //construct a CIMExpressionInfo
  var arcade_expr = new CIMExpressionInfo()
  {
    Expression = query.ToString(),
    //Return type can be string, numeric, or default
    //When set to default, addin is responsible for determining
    //the return type
    ReturnType = ExpressionReturnType.Default
  };

  //Construct an evaluator
  //select the relevant profile - it must support Pro and it must
  //contain any profile variables you are using in your expression.
  //Consult: https://developers.arcgis.com/arcade/profiles/
  using (var arcade = ArcadeScriptEngine.Instance.CreateEvaluator(
                          arcade_expr, ArcadeProfile.Popups))
  {
    //Provision  values for any profile variables referenced...
    //in our case '$layer'
    var variables = new List<KeyValuePair<string, object>>() {
        new KeyValuePair<string, object>("$layer", featLayer)
      };
    //evaluate the expression
    try
    {
      var result = arcade.Evaluate(variables).GetResult();
      System.Diagnostics.Debug.WriteLine($"Result: {result.ToString()}");
    }
    //handle any exceptions
    catch (InvalidProfileVariableException ipe)
    {
      //something wrong with the profile variable specified
      //TODO...
    }
    catch (EvaluationException ee)
    {
      //something wrong with the query evaluation
      //TODO...
    }

  }
});

Basic Query using Features

//Consult https://github.com/Esri/arcade-expressions/ and
//https://developers.arcgis.com/arcade/ for more examples
//and arcade reference

QueuedTask.Run(() =>
{
  //construct an expression
  var query = @"$feature.AreaInAcres * 43560.0";//convert acres to ft 2

  //construct a CIMExpressionInfo
  var arcade_expr = new CIMExpressionInfo()
  {
    Expression = query.ToString(),
    //Return type can be string, numeric, or default
    //When set to default, addin is responsible for determining
    //the return type
    ReturnType = ExpressionReturnType.Default
  };

  //Construct an evaluator
  //select the relevant profile - it must support Pro and it must
  //contain any profile variables you are using in your expression.
  //Consult: https://developers.arcgis.com/arcade/profiles/
  using (var arcade = ArcadeScriptEngine.Instance.CreateEvaluator(
                          arcade_expr, ArcadeProfile.Popups))
  {
    //we are evaluating the expression against all features
    using (var rc = featLayer.Search())
    {

      while (rc.MoveNext())
      {
        //Provision  values for any profile variables referenced...
        //in our case '$feature'
        var variables = new List<KeyValuePair<string, object>>() {
          new KeyValuePair<string, object>("$feature", rc.Current)
        };
        //evaluate the expression (per feature in this case)
        try
        {
          var result = arcade.Evaluate(variables).GetResult();
          var val = ((double)result).ToString("0.0#");
          System.Diagnostics.Debug.WriteLine(
            $"{rc.Current.GetObjectID()} area: {val} ft2");
        }
        //handle any exceptions
        catch (InvalidProfileVariableException ipe)
        {
          //something wrong with the profile variable specified
          //TODO...
        }
        catch (EvaluationException ee)
        {
          //something wrong with the query evaluation
          //TODO...
        }
      }
    }
  }
});

Retrieve features using FeatureSetByName

//Consult https://github.com/Esri/arcade-expressions/ and
//https://developers.arcgis.com/arcade/ for more examples
//and arcade reference

var map = MapView.Active.Map;
QueuedTask.Run(() =>
{
  //construct a query
  var query = new StringBuilder();
  var layer_name = "USA Current Wildfires - Current Incidents";
  //https://developers.arcgis.com/arcade/function-reference/featureset_functions/
  query.AppendLine(
    $"var features = FeatureSetByName($map,'{layer_name}', ['*'], false);");
  query.AppendLine("return Count(features);");

  //construct a CIMExpressionInfo
  var arcade_expr = new CIMExpressionInfo()
  {
    Expression = query.ToString(),
    //Return type can be string, numeric, or default
    //When set to default, addin is responsible for determining
    //the return type
    ReturnType = ExpressionReturnType.Default
  };

  //Construct an evaluator
  //select the relevant profile - it must support Pro and it must
  //contain any profile variables you are using in your expression.
  //Consult: https://developers.arcgis.com/arcade/profiles/
  using (var arcade = ArcadeScriptEngine.Instance.CreateEvaluator(
                          arcade_expr, ArcadeProfile.Popups))
  {
    //Provision  values for any profile variables referenced...
    //in our case '$map'
    var variables = new List<KeyValuePair<string, object>>() {
        new KeyValuePair<string, object>("$map", map)
      };
    //evaluate the expression
    try
    {
      var result = arcade.Evaluate(variables).GetResult();
      System.Diagnostics.Debug.WriteLine($"Result: {result.ToString()}");
    }
    //handle any exceptions
    catch (InvalidProfileVariableException ipe)
    {
      //something wrong with the profile variable specified
      //TODO...
    }
    catch (EvaluationException ee)
    {
      //something wrong with the query evaluation
      //TODO...
    }
  }
});

Retrieve features using Filter

//Consult https://github.com/Esri/arcade-expressions/ and
//https://developers.arcgis.com/arcade/ for more examples
//and arcade reference

QueuedTask.Run(() =>
{
  //construct a query
  var query = new StringBuilder();
  //https://developers.arcgis.com/arcade/function-reference/featureset_functions/
  query.AppendLine(
    "var features = Filter($layer, 'DailyAcres is not NULL');");
  query.AppendLine("return Count(features);");

  //construct a CIMExpressionInfo
  var arcade_expr = new CIMExpressionInfo()
  {
    Expression = query.ToString(),
    //Return type can be string, numeric, or default
    //When set to default, addin is responsible for determining
    //the return type
    ReturnType = ExpressionReturnType.Default
  };

  //Construct an evaluator
  //select the relevant profile - it must support Pro and it must
  //contain any profile variables you are using in your expression.
  //Consult: https://developers.arcgis.com/arcade/profiles/
  using (var arcade = ArcadeScriptEngine.Instance.CreateEvaluator(
                          arcade_expr, ArcadeProfile.Popups))
  {
    //Provision  values for any profile variables referenced...
    //in our case '$layer'
    var variables = new List<KeyValuePair<string, object>>() {
        new KeyValuePair<string, object>("$layer", featLayer)
      };
    //evaluate the expression
    try
    {
      var result = arcade.Evaluate(variables).GetResult();
      System.Diagnostics.Debug.WriteLine($"Result: {result.ToString()}");
    }
    //handle any exceptions
    catch (InvalidProfileVariableException ipe)
    {
      //something wrong with the profile variable specified
      //TODO...
    }
    catch (EvaluationException ee)
    {
      //something wrong with the query evaluation
      //TODO...
    }
  }
});

Calculate basic statistics with Math functions

//Consult https://github.com/Esri/arcade-expressions/ and
//https://developers.arcgis.com/arcade/ for more examples
//and arcade reference

QueuedTask.Run(() =>
{
  //construct a query
  var query = new StringBuilder();
  //https://developers.arcgis.com/arcade/function-reference/math_functions

  query.AppendLine("var features = Filter($layer, 'DailyAcres is not NULL');");

  query.AppendLine("var count_feat = Count(features);");
  query.AppendLine("var sum_feat = Sum(features, 'DailyAcres');");
  query.AppendLine("var max_feat = Max(features, 'DailyAcres');");
  query.AppendLine("var min_feat = Min(features, 'DailyAcres');");
  query.AppendLine("var avg_feat = Average(features, 'DailyAcres');");

  query.AppendLine("var answer = [count_feat, sum_feat, max_feat, min_feat, avg_feat]");
  query.AppendLine("return Concatenate(answer,'|');");

  //construct a CIMExpressionInfo
  var arcade_expr = new CIMExpressionInfo()
  {
    Expression = query.ToString(),
    //Return type can be string, numeric, or default
    //When set to default, addin is responsible for determining
    //the return type
    ReturnType = ExpressionReturnType.Default
  };

  //Construct an evaluator
  //select the relevant profile - it must support Pro and it must
  //contain any profile variables you are using in your expression.
  //Consult: https://developers.arcgis.com/arcade/profiles/
  using (var arcade = ArcadeScriptEngine.Instance.CreateEvaluator(
                          arcade_expr, ArcadeProfile.Popups))
  {
    //Provision  values for any profile variables referenced...
    //in our case '$layer'
    var variables = new List<KeyValuePair<string, object>>() {
        new KeyValuePair<string, object>("$layer", featLayer)
      };
    //evaluate the expression
    try
    {
      var result = arcade.Evaluate(variables).GetResult();
      System.Diagnostics.Debug.WriteLine($"Result: {result.ToString()}");
    }
    //handle any exceptions
    catch (InvalidProfileVariableException ipe)
    {
      //something wrong with the profile variable specified
      //TODO...
    }
    catch (EvaluationException ee)
    {
      //something wrong with the query evaluation
      //TODO...
    }
  }
});

Using FeatureSet functions Filter and Intersects

//Consult https://github.com/Esri/arcade-expressions/ and
//https://developers.arcgis.com/arcade/ for more examples
//and arcade reference

var map = MapView.Active.Map;
QueuedTask.Run(() =>
{
  //construct a query
  var query = new StringBuilder();
  //https://developers.arcgis.com/arcade/function-reference/featureset_functions/

  //Assume we have two layers - Oregon Counties (poly) and Crimes (points). Crimes
  //is from the Pro SDK community sample data.
  //Select all crime points within the relevant county boundaries and sum the count
  query.AppendLine("var results = [];");

  query.AppendLine("var counties = FeatureSetByName($map, 'Oregon_Counties', ['*'], true);");

  //'Clackamas','Multnomah','Washington'
  query.AppendLine("var sel_counties = Filter(counties, 'DHS_Districts IN (2, 15, 16)');");

  query.AppendLine("for(var county in sel_counties) {");
  query.AppendLine("   var name = county.County_Name;");
  query.AppendLine("   var cnt_crime = Count(Intersects($layer, Geometry(county)));");
  query.AppendLine("   Insert(results, 0, cnt_crime);");
  query.AppendLine("   Insert(results, 0, name);");
  query.AppendLine("}");

  query.AppendLine("return Concatenate(results,'|');");

  //construct a CIMExpressionInfo
  var arcade_expr = new CIMExpressionInfo()
  {
    Expression = query.ToString(),
    //Return type can be string, numeric, or default
    //When set to default, addin is responsible for determining
    //the return type
    ReturnType = ExpressionReturnType.Default
  };

  //Construct an evaluator
  //select the relevant profile - it must support Pro and it must
  //contain any profile variables you are using in your expression.
  //Consult: https://developers.arcgis.com/arcade/profiles/
  using (var arcade = ArcadeScriptEngine.Instance.CreateEvaluator(
                          arcade_expr, ArcadeProfile.Popups))
  {
    //Provision  values for any profile variables referenced...
    //in our case '$layer' and '$map'
    var variables = new List<KeyValuePair<string, object>>() {
        new KeyValuePair<string, object>("$layer", crimes_layer),
        new KeyValuePair<string, object>("$map", map)
      };
    //evaluate the expression
    try
    {
      var result = arcade.Evaluate(variables).GetResult();

      var results = result.ToString().Split('|', StringSplitOptions.None);
      var entries = results.Length / 2;
      int i = 0;
      for (var e = 0; e < entries; e++)
      {
        var name = results[i++];
        var count = results[i++];
        System.Diagnostics.Debug.WriteLine($"'{name}' crime count: {count}");
      }
    }
    //handle any exceptions
    catch (InvalidProfileVariableException ipe)
    {
      //something wrong with the profile variable specified
      //TODO...
    }
    catch (EvaluationException ee)
    {
      //something wrong with the query evaluation
      //TODO...
    }
  }
});

Evaluating Expressions

Evaluating an Arcade Labelling Expression

//Consult https://github.com/Esri/arcade-expressions/ and
//https://developers.arcgis.com/arcade/ for more examples
//and arcade reference

var map = MapView.Active.Map;
QueuedTask.Run(() =>
{
  //Assume we a layer - Oregon County (poly) that has an arcade labelling
  //expression and we want to evaluate that interactively...
  var def = oregon_cnts.GetDefinition() as CIMFeatureLayer;
  //Get the label class
  var label_class = def.LabelClasses
                     .FirstOrDefault(lc => {
                       return lc.Name == "Arcade_Example_1" &&
                              lc.ExpressionEngine == LabelExpressionEngine.Arcade;
                     });
  if (label_class == null)
    return;

  //evaluate the label expression against the features
  var expr_info = new CIMExpressionInfo()
  {
    Expression = label_class.Expression,
    ReturnType = ExpressionReturnType.String
  };

  //https://developers.arcgis.com/arcade/profiles/labeling/
  using (var arcade = ArcadeScriptEngine.Instance.CreateEvaluator(
                                            expr_info, ArcadeProfile.Labeling))
  {
    //loop through the features
    using (var rc = oregon_cnts.Search())
    {
      while (rc.MoveNext())
      {
        var variables = new List<KeyValuePair<string, object>>() {
          new KeyValuePair<string, object>("$feature", rc.Current)
        };
        var result = arcade.Evaluate(variables).GetResult();
        //output
        System.Diagnostics.Debug.WriteLine(
           $"[{rc.Current.GetObjectID()}]: {result}");
      }
    }
  }
});

Evaluating Arcade Visual Variable Expressions on a Renderer

//Consult https://github.com/Esri/arcade-expressions/ and
//https://developers.arcgis.com/arcade/ for more examples
//and arcade reference

var mv = MapView.Active;
var map = mv.Map;

QueuedTask.Run(() =>
{
  //Assume we a layer - Oregon County (poly) that is using Visual Variable
  //expressions that we want to evaluate interactively...
  var def = oregon_cnts.GetDefinition() as CIMFeatureLayer;

  //Most all feature renderers have a VisualVariable collection
  var renderer = def.Renderer as CIMUniqueValueRenderer;
  var vis_variables = renderer.VisualVariables?.ToList() ??
                        new List<CIMVisualVariable>();
  if (vis_variables.Count == 0)
    return;//there are none
  var vis_var_with_expr = new Dictionary<string, string>();
  //see if any are using expressions
  foreach (var vv in vis_variables)
  {
    if (vv is CIMColorVisualVariable cvv)
    {
      if (!string.IsNullOrEmpty(cvv.ValueExpressionInfo?.Expression))
        vis_var_with_expr.Add("Color", cvv.ValueExpressionInfo?.Expression);
    }
    else if (vv is CIMTransparencyVisualVariable tvv)
    {
      if (!string.IsNullOrEmpty(tvv.ValueExpressionInfo?.Expression))
        vis_var_with_expr.Add("Transparency", tvv.ValueExpressionInfo?.Expression);
    }
    else if (vv is CIMSizeVisualVariable svv)
    {
      if (!string.IsNullOrEmpty(svv.ValueExpressionInfo?.Expression))
        vis_var_with_expr.Add("Outline", svv.ValueExpressionInfo?.Expression);
    }
  }
  if (vis_var_with_expr.Count == 0)
    return;//there arent any with expressions

  //loop through the features (outer)
  //per feature evaluate each visual variable.... (inner)
  //....
  //the converse is to loop through the expressions (outer)
  //then per feature evaluate the expression (inner)
  using (var rc = oregon_cnts.Search())
  {
    while (rc.MoveNext())
    {
      foreach (var kvp in vis_var_with_expr)
      {
        var expr_info = new CIMExpressionInfo()
        {
          Expression = kvp.Value,
          ReturnType = ExpressionReturnType.Default
        };
        //per feature eval each expression...
        using (var arcade = ArcadeScriptEngine.Instance.CreateEvaluator(
                                    expr_info, ArcadeProfile.Visualization))
        {

          var variables = new List<KeyValuePair<string, object>>() {
            new KeyValuePair<string, object>("$feature", rc.Current)
          };
          //note 2D maps can also have view scale...
          //...if necessary...
          if (mv.ViewingMode == MapViewingMode.Map)
          {
            variables.Add(new KeyValuePair<string, object>(
              "$view.scale", mv.Camera.Scale));
          }
          var result = arcade.Evaluate(variables).GetResult().ToString();
          //output
          System.Diagnostics.Debug.WriteLine(
             $"[{rc.Current.GetObjectID()}] '{kvp.Key}': {result}");
        }
      }
    }
  }

  ////foreach (var kvp in vis_var_with_expr)
  ////{
  ////  var expr_info = new CIMExpressionInfo()
  ////  {
  ////    Expression = kvp.Value,
  ////    ReturnType = ExpressionReturnType.Default
  ////  };

  ////  using (var arcade = ArcadeScriptEngine.Instance.CreateEvaluator(
  ////                                  expr_info, ArcadeProfile.Visualization))
  ////  {
  ////    //loop through the features
  ////    using (var rc = oregon_cnts.Search())
  ////    {
  ////      while (rc.MoveNext())
  ////      {
  ////        var variables = new List<KeyValuePair<string, object>>() {
  ////          new KeyValuePair<string, object>("$feature", rc.Current)
  ////        };

  ////        var result = arcade.Evaluate(variables).GetResult();
  ////        //output
  ////        //...
  ////      }
  ////    }
  ////  }
  ////}
});

Modify renderer using Arcade

var lyr = MapView.Active.Map.GetLayersAsFlattenedList().OfType<FeatureLayer>().FirstOrDefault(f => f.ShapeType == esriGeometryType.esriGeometryPolygon);
if (lyr == null) return;
QueuedTask.Run(() =>
{
  // GetRenderer from Layer (assumes it is a unique value renderer)
  var uvRenderer = lyr.GetRenderer() as CIMUniqueValueRenderer;
  if (uvRenderer == null) return;
  //layer has STATE_NAME field
  //community sample Data\Admin\AdminSample.aprx
  string expression = "if ($view.scale > 21000000) { return $feature.STATE_NAME } else { return 'All' }";
  CIMExpressionInfo updatedExpressionInfo = new CIMExpressionInfo
  {
    Expression = expression,
    Title = "Custom" // can be any string used for UI purpose.
  };
  //set the renderer's expression
  uvRenderer.ValueExpressionInfo = updatedExpressionInfo;

  //SetRenderer on Layer
  lyr.SetRenderer(uvRenderer);
});

Modify label expression using Arcade

var lyr = MapView.Active.Map.GetLayersAsFlattenedList().OfType<FeatureLayer>().FirstOrDefault(f => f.ShapeType == esriGeometryType.esriGeometryPolygon);
if (lyr == null) return;
QueuedTask.Run(() =>
{
  //Get the layer's definition
  //community sample Data\Admin\AdminSample.aprx
  var lyrDefn = lyr.GetDefinition() as CIMFeatureLayer;
  if (lyrDefn == null) return;
  //Get the label classes - we need the first one
  var listLabelClasses = lyrDefn.LabelClasses.ToList();
  var theLabelClass = listLabelClasses.FirstOrDefault();
  //set the label class Expression to use the Arcade expression
  theLabelClass.Expression = "return $feature.STATE_NAME + TextFormatting.NewLine + $feature.POP2000;";
  //Set the label definition back to the layer.
  lyr.SetDefinition(lyrDefn);
});

Evaluate AttributeRule Expression

//Consult https://github.com/Esri/arcade-expressions/ and
//https://developers.arcgis.com/arcade/profiles/attribute-rules/ for
//more examples and arcade reference

QueuedTask.Run(() =>
{
  //Retrieve the desired feature class/table
  var def = featLayer.GetFeatureClass().GetDefinition();
  
  //get the desired attribute rule whose expression is to be
  //evaluated.
  //AttributeRuleType.All, Calculation, Constraint, Validation
  var validation_rule = def.GetAttributeRules(
                              AttributeRuleType.Validation).FirstOrDefault();
  if (validation_rule == null)
    return;

  //Get the expression
  var expr = validation_rule.GetScriptExpression();
  //construct a CIMExpressionInfo
  var arcade_expr = new CIMExpressionInfo()
  {
    Expression = expr,
    //Return type can be string, numeric, or default
    ReturnType = ExpressionReturnType.Default
  };

  System.Diagnostics.Debug.WriteLine($"Evaluating {expr}:");
  //Construct an evaluator
  //we are using ArcadeProfile.AttributeRules profile...
  //Consult: https://developers.arcgis.com/arcade/profiles/
  using (var arcade = ArcadeScriptEngine.Instance.CreateEvaluator(
                          arcade_expr, ArcadeProfile.AttributeRuleValidation))
  {
    //we are evaluating the expression against all features
    using (var rc = featLayer.Search())
    {

      while (rc.MoveNext())
      {
        //Provision  values for any profile variables referenced...
        //in our case we assume '$feature'
        //...use arcade.ProfileVariablesUsed() if necessary...
        var variables = new List<KeyValuePair<string, object>>() {
          new KeyValuePair<string, object>("$feature", rc.Current)
        };

        //evaluate the expression per feature
        try
        {
          var result = arcade.Evaluate(variables).GetResult();
          //'Validation' attribute rules return true or false...
          var valid = System.Boolean.Parse(result.ToString());
          System.Diagnostics.Debug.WriteLine(
            $"{rc.Current.GetObjectID()} valid: {valid}");
        }
        //handle any exceptions
        catch (InvalidProfileVariableException ipe)
        {
          //something wrong with the profile variable specified
          //TODO...
        }
        catch (EvaluationException ee)
        {
          //something wrong with the query evaluation
          //TODO...
        }
      }
    }
  }
});
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