topic Re: Date Attribute Field Update in ArcGIS API for Silverlight Questions

Date Attribute Field Update

JingjingLi — Mon, 21 Mar 2011 22:07:07 GMT

I am facing an issue of updating Date field using null value. The Date field on the feature class is nullable. I created a feature service and loaded it in a silverlight app. I want to make a value in the field to be blank (null). But the attributes property of a graphic is IDictioanry<string, object> which is not nullable. How can I make it accept a null value?
Just like Graphic.Attributes["DateField"] = null

Re: Date Attribute Field Update

JenniferNery — Tue, 22 Mar 2011 01:16:40 GMT

Can you share the service end point field information?

For example, when I visit this service end point from my web browser: http://sampleserver3.arcgisonline.com/ArcGIS/rest/services/HomelandSecurity/operations/FeatureServer/0

collection_time (Type: esriFieldTypeDate, Alias: Collection Date, Length: 36, Editable: True)

This means there is a required length to the field.

Re: Date Attribute Field Update

JingjingLi — Tue, 22 Mar 2011 04:01:48 GMT

UPDATEDATE (Type: esriFieldTypeDate, Alias: UPDATEDATE, Length: 36, Editable: True)

And 'Allow Null values' on the field is set to true.
This is actually the default Date field setting. I don't think I can create a Date field with a specific length. Does this mean you cannot update the date value to null in silverlight?

Re: Date Attribute Field Update

dotMorten_esri — Tue, 22 Mar 2011 17:52:26 GMT

Graphic.Attributes["DateField"] = null should work.
Are you saying it doesn't? It not, what happens when you try that?

Re: Date Attribute Field Update

JenniferNery — Tue, 22 Mar 2011 18:47:22 GMT

I think that since you gave a length requirement, a validation exception will be thrown if this is not met. If you made g.Attributes["UPDATEDATE"] = null.

If you remove this length requirement, I think you should be able to set it to a null value without validation exception.

Re: Date Attribute Field Update

JingjingLi — Fri, 10 Dec 2021 23:37:40 GMT

Graphic.Attributes["DateField"] = null should work.
Are you saying it doesn't? It not, what happens when you try that?

No it does not work. It throws a NullReferenceException.

foreach (ESRI.ArcGIS.Client.Graphic g in fl.Graphics)
                {
                    if ((int)g.Attributes["OBJECTID"] == objid)
                    {
                        IDictionary<string, object> att = g.Attributes;
                        if (att["UPDATETIME"] != null)
                        {
                            att["UPDATETIME"] = "";
                        }

                        if (att["UPDATEDATE"] != null)
                        {
                            //UpdateDate is a Date field
                            att["UPDATEDATE"] = null;
                        }

                        if (att["DESCRIPTION"] != null)
                        {
                            att["DESCRIPTION"] = "";
                        }
                        
                    }
                }

It's strange. For these records that have null value in the date field. I am able to get the null value from the Attributes property. Just not able to write a null value to it.

Re: Date Attribute Field Update

JingjingLi — Wed, 23 Mar 2011 01:29:25 GMT

I think that since you gave a length requirement, a validation exception will be thrown if this is not met. If you made g.Attributes["UPDATEDATE"] = null.

If you remove this length requirement, I think you should be able to set it to a null value without validation exception.

How can you remove the length of a Date field? I think by default you can only setup the field type and nullable for a Date field.

Re: Date Attribute Field Update

PreetiMaske — Wed, 23 Mar 2011 16:15:58 GMT

I guess DateTime is Non-Nullable DataType so setting it to null won't work.
Try setting it to null as follows:
g.Attributes["UPDATEDATE"] = new DateTime?();

Re: Date Attribute Field Update

JenniferNery — Fri, 10 Dec 2021 23:37:43 GMT

You are right, by default DateField has a default length of 36.

You can try the following feature service that has a nullable DateField. Setting the attribute value to null does not raise any exception. You can wire up to EndSaveEdits and SaveEditsFailed to see that this new value is actually saved.

FeatureLayer layer = new FeatureLayer() { Url = "http://sampleserver3.arcgisonline.com/ArcGIS/rest/services/HomelandSecurity/operations/FeatureServer/0", OutFields = new ESRI.ArcGIS.Client.Tasks.OutFields() { "*" } };
layer.Initialized += (s,e) =>
{
 layer.Update();
};
layer.UpdateCompleted += (s,e) =>
{
 var graphic = layer.Graphics.FirstOrDefault(g => (int)g.Attributes["objectid"] == 105635);
 graphic.Attributes["collection_time"] = null;
};
layer.Initialize();

If you are still experiencing issues please explain your use case with details about the data and application workflow so we can reproduce it here. Thanks.

Re: Date Attribute Field Update

JingjingLi — Wed, 23 Mar 2011 23:01:29 GMT

I guess DateTime is Non-Nullable DataType so setting it to null won't work.
Try setting it to null as follows:
g.Attributes["UPDATEDATE"] = new DateTime?();

It throws a NullReferenceException error. I think it is the same as

g.Attributes["UPDATEDATE"] = null

Re: Date Attribute Field Update

JenniferNery — Wed, 23 Mar 2011 23:42:06 GMT

g. Attributes["UPDATEDATE"] = null

Is g null? or is Attributes null? Check also that g.Attributes.ContainsKey("UPDATEDATE") maybe this returns null because field name does not match or FeatureLayer.OutFields does not include this field.

Re: Date Attribute Field Update

JingjingLi — Fri, 10 Dec 2021 23:37:45 GMT

You are right, by default DateField has a default length of 36.

You can try the following feature service that has a nullable DateField. Setting the attribute value to null does not raise any exception. You can wire up to EndSaveEdits and SaveEditsFailed to see that this new value is actually saved.
FeatureLayer layer = new FeatureLayer() { Url = "http://sampleserver3.arcgisonline.com/ArcGIS/rest/services/HomelandSecurity/operations/FeatureServer/0", OutFields = new ESRI.ArcGIS.Client.Tasks.OutFields() { "*" } };
layer.Initialized += (s,e) =>
{
 layer.Update();
};
layer.UpdateCompleted += (s,e) =>
{
 var graphic = layer.Graphics.FirstOrDefault(g => (int)g.Attributes["objectid"] == 105635);
 graphic.Attributes["collection_time"] = null;
};
layer.Initialize();
If you are still experiencing issues please explain your use case with details about the data and application workflow so we can reproduce it here. Thanks.

I tried the easiest way to populate the field but still get a NullReferenceException error.

ESRI.ArcGIS.Client.FeatureLayer fl = theMap.Layers["flyr_RoadClosureLocations"] as ESRI.ArcGIS.Client.FeatureLayer;
            foreach (ESRI.ArcGIS.Client.Graphic g in fl.Graphics)
            {
                if (g.Attributes["UPID"].ToString() == "CAB_035")
                {
                    MessageBox.Show(g.Attributes["UPDATEDATE"].ToString());
                    g.Attributes["UPDATEDATE"] = null;
                }
            }

I uploaded three screenshots to show the settings of the feature class, the layer and the feature service. In the Silverlight App, I tried both 2.1 and 2.2 API but get the same error.
Environment:
ArcSDE 10 Sp1
ArcGIS Server 10 Sp1

Re: Date Attribute Field Update

JingjingLi — Fri, 10 Dec 2021 23:37:49 GMT

Finally I found the reason. The application has a FeatureDataGrid binding to the FeatureLayer. I have to set both FeatureDataGrid.Map and FeatureDataGrid.GraphicsLayer to null before I can assign a null value to g.Attribute["UPDATEDATE"]. See code below,

theFeatureDataGrid.Map = null;
            theFeatureDataGrid.GraphicsLayer = null;
            ESRI.ArcGIS.Client.FeatureLayer fl = theMap.Layers["flyr_RoadClosureLocations"] as ESRI.ArcGIS.Client.FeatureLayer;
            foreach (ESRI.ArcGIS.Client.Graphic g in fl.Graphics)
            {
                if (g.Attributes["UPID"].ToString() == "CAB_035")
                {
                    g.Attributes["UPDATEDATE"] = null;
                }
            }
            theFeatureDataGrid.Map = theMap;
            theFeatureDataGrid.GraphicsLayer = fl;

And it works.

Re: Date Attribute Field Update

JenniferNery — Thu, 24 Mar 2011 15:27:14 GMT

Thank you for reporting this. We'll try to get FeatureDataGrid fixed in the future release.