topic Re: C# Retrieving field data type from a FeatureLayer/Class in ArcGIS Pro SDK Questions

C# Retrieving field data type from a FeatureLayer/Class

MikeRatcliffe — Mon, 26 Mar 2018 13:33:55 GMT

I want to parse user input through a field data type converter (if...else if) so that I don't get a "Data Type Mismatch" from my QueryFilter/SpatialQueryFilter. However, I'm having trouble retrieving the actual field data type from the FeatureLayer or FeatureClass. I can get to the Field name for the query, but not the data type (Text, Int, Double, Long, etc...).

Re: C# Retrieving field data type from a FeatureLayer/Class

RichRuh — Mon, 26 Mar 2018 15:01:51 GMT

Given the FeatureClass, you can get a FeatureClassDefinition object by calling FeatureClass.GetDefinition().

From the FeatureClassDefinition you can call FindField() to find the field index, given the name. With that and a fields collection from FeatureClassDefinition.GetFields(), you can get a Field object.

Finally, the Field object has a FieldType property.

Re: C# Retrieving field data type from a FeatureLayer/Class

MikeRatcliffe — Mon, 26 Mar 2018 15:58:24 GMT

Thanks for pointing to FeatureClassDefinition, Rich.

I'm still fuzzy on acquiring the Field object...

Re: C# Retrieving field data type from a FeatureLayer/Class

UmaHarano — Sun, 12 Dec 2021 09:12:47 GMT

Hi Mike,

Check out the Renderer community sample. There is code in there that gets a feature layer's numeric field.

In particular, check out the following 2 methods:

Given a feature layer, this method get's the first numeric field.

internal static string GetNumericField(FeatureLayer featureLayer)
        {
            //Get all the visible numeric fields for the layer.
            var numericField = featureLayer.GetFieldDescriptions().FirstOrDefault(f => IsNumericFieldType(f.Type) && f.IsVisible);
            return numericField.Name;
        }‍‍‍‍‍‍

This is the helper method that does the work:

 internal static bool IsNumericFieldType(FieldType type)
        {
            switch (type)
            {
                case FieldType.Double:
                case FieldType.Integer:
                case FieldType.Single:
                case FieldType.SmallInteger:
                    return true;
                default:
                    return false;
            }
        }‍‍‍‍‍‍‍‍‍‍‍‍‍

Thanks

Uma

Re: C# Retrieving field data type from a FeatureLayer/Class

MikeRatcliffe — Mon, 26 Mar 2018 18:17:57 GMT

Thanks, Uma.

That isn't entirely what I'm after.

I'm collecting from a sub-form user input (string) & fieldname (combobox) from a featurelayer/class as variables for a queryfilter/spatialqueryfilter on the main-form. I need to know the fieldname's FIELDTYPE to parse appropriately for the query filter. Other wise I get the "data type mismatch in criteria expression."

I'm looking for the FIELDTYPE of a selected column.

I followed Rich's lead from above, but am troubleshooting the FIELD object, so I can get the correct FIELDTYPE.

thanks.

Re: C# Retrieving field data type from a FeatureLayer/Class

MikeRatcliffe — Mon, 26 Mar 2018 19:12:43 GMT

This is where I ended up...

public async void MnlSrchCmbobx_SelectionChangeCommitted(object sender, EventArgs e)
{
var attfn = MnlSrchCmbobx.Text; //string choice from combobox (search field)
Form1.GVar.ms_attfn = attfn; //string to global variable

await ActMap(); //active map checker

Map map = MapView.Active.Map;

var srch_lyr = map.FindLayers(lyr).FirstOrDefault() as FeatureLayer; //layer locator from "lyr" in activemap TOC

await QueuedTask.Run(() =>
{

TableDefinition srch_FCD = srch_lyr.GetTable().GetDefinition(); //table definition of featurelayer

var Find_Fld = srch_FCD.FindField(attfn); //find the search field index

var Get_Flds = srch_FCD.GetFields(); //get the readonly collection of fields from the table

Field ms_field = Get_Flds.ElementAt(Find_Fld); //Field object: via search field index from collection

var FldTp = ms_field.FieldType.ToString(); //get fieldtype as a string

Form1.GVar.ms_v_datatype = FldTp; //assign fieldtype to global variable

});

AsetSrchFldDTLbl.Text = Form1.GVar.ms_v_datatype; //test output on sub-form to a label.
}

Thanks, Rich and Uma.