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List Fields In Feature In Pro SDK

MapVis

I am trying to get a list of the fields in a feature inside the project default geodatabase.

what is the c# pro sdk equivalent of the python below?

for lyr in m.listLayers():
            if lyr.name == "layer":
                field_names = []
                fields = arcpy.ListFields(lyr)
                for field in fields:
                    field_names.append(field.name)

Do i have to go through the geodatabse API with a feature definition to get that list? like below. or is there a shorter or more prefered way?

using (Geodatabase fileGeodatabase = new Geodatabase(new FileGeodatabaseConnectionPath((uri))))

using (FeatureClass featureClass = fileGeodatabase.OpenDataset<FeatureClass>(matchLyr))

{

FeatureClassDefinition LyrDefinition = featureClass.GetDefinition();

IReadOnlyList<Field> fields = LyrDefinition.GetFields();

List<string> fieldList = new List<string>();

foreach (var fld in fields)

{

fieldList.Add(fld.Name);

Debug.WriteLine(fld.Name);

}

return fieldList;

}

Najděte více příspěvků označených jako

Accepted answers

RichRuh

I was confused by this at first too. The statement

<SPAN class="keyword token">return</SPAN> matchField<SPAN class="line-numbers-rows"><SPAN>‍</SPAN></SPAN>

exits the delegate passed to QueuedTask.Run(). You still have to return a value from the GetFieldList() function.

You *could* say

<SPAN class="keyword token">return</SPAN> <SPAN class="keyword token">await</SPAN> ArcGIS<SPAN class="punctuation token">.</SPAN>Desktop<SPAN class="punctuation token">.</SPAN>Framework<SPAN class="punctuation token">.</SPAN>ThreadingTasks<SPAN class="punctuation token">.</SPAN>QueuedTask<SPAN class="punctuation token">.</SPAN><SPAN class="token function">Run</SPAN><SPAN class="punctuation token">(</SPAN><SPAN class="punctuation token">.</SPAN><SPAN class="punctuation token">.</SPAN><SPAN class="punctuation token">.</SPAN><SPAN class="line-numbers-rows"><SPAN>‍</SPAN></SPAN>

However my colleague Charles Macleod‌ recommended the following:

public static async Task<string> GetFieldList(…

return await ArcGIS.Desktop.Framework.Threading.Tasks.QueuedTask.Run(() =>

And then await GetFieldList() in the calling function.

All comments

MapVis

awaiting GetFieldList() from Charles worked great. Thanks.

RichRuh

I was confused by this at first too. The statement

<SPAN class="keyword token">return</SPAN> matchField<SPAN class="line-numbers-rows"><SPAN>‍</SPAN></SPAN>

exits the delegate passed to QueuedTask.Run(). You still have to return a value from the GetFieldList() function.

You *could* say

<SPAN class="keyword token">return</SPAN> <SPAN class="keyword token">await</SPAN> ArcGIS<SPAN class="punctuation token">.</SPAN>Desktop<SPAN class="punctuation token">.</SPAN>Framework<SPAN class="punctuation token">.</SPAN>ThreadingTasks<SPAN class="punctuation token">.</SPAN>QueuedTask<SPAN class="punctuation token">.</SPAN><SPAN class="token function">Run</SPAN><SPAN class="punctuation token">(</SPAN><SPAN class="punctuation token">.</SPAN><SPAN class="punctuation token">.</SPAN><SPAN class="punctuation token">.</SPAN><SPAN class="line-numbers-rows"><SPAN>‍</SPAN></SPAN>

However my colleague Charles Macleod‌ recommended the following:

public static async Task<string> GetFieldList(…

return await ArcGIS.Desktop.Framework.Threading.Tasks.QueuedTask.Run(() =>

And then await GetFieldList() in the calling function.

MapVis

Thanks Rich it seems to be working but im getting an error "not all code paths return a value". Im confused if it runs the task, gets the table definition, gets the field list, adds the field name to a list, intersects 2 lists to get the first matching value, then returns the matching value, what other code path would there be?

public static async Task<string> GetFieldList(string layer, string projGDBPath, List<string> fieldOneOptions)

{

await ArcGIS.Desktop.Framework.Threading.Tasks.QueuedTask.Run(() =>

{

using (Geodatabase fileGeodatabase = new Geodatabase(new FileGeodatabaseConnectionPath(new Uri(projGDBPath))))

using (FeatureClassDefinition featureClass = fileGeodatabase.GetDefinition<FeatureClassDefinition>(layer))

{

IReadOnlyList<Field> fields = featureClass.GetFields();

List<string> fieldList = new List<string>();

foreach (var fld in fields)

{

fieldList.Add(fld.Name)

}

string matchField = fieldOneOptions.Intersect(fieldList).FirstOrDefault().ToString();

return matchField;

}

});

}

NarelleChedzey

If you already have the layer you can also do something similar to the following

IReadOnlyList<ArcGIS.Core.Data.Field> fields = null;
List<string> fieldList = new List<string>();
await QueuedTask.Run(() =>
{
ArcGIS.Core.Data.Table table = theFeatureLayer.GetTable();
if (table != null)
{
ArcGIS.Core.Data.TableDefinition def = table.GetDefinition();
fields = def.GetFields();
foreach (var fld in fields)
{
fieldList.Add(fld.Name);
Debug.WriteLine(fld.Name);
}
}
});

You still end up looking at the feature layer / table definition, but because you have the layer you don't need the additional Geodatabase object.

RichRuh

You can actually call Geodatabase.GetDefinition<FeatureClassDefinition>() to go directly from the file geodatabase to the definition without incurring the overhead of opening the table. Other than that, this code is the correct way to get the field list.

--Rich

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