topic Re: QueryTable Error in ArcGIS Pro SDK Questions

QueryTable Error

ThiPham12 — Wed, 08 Dec 2021 03:17:22 GMT

I am trying to use query table to create a list of strings, mukey, associated with specific counties, to use for further geoprocessing with other tables in the same geodatabase. I created a dictionary with the county as the key and mukey as the value to query the list of mukeys. However, I have an error: CS1061 at "MUResults[county].Add(mukey)" saying there is no accessible extension method to Add. I am wondering what I can do to resolve this problem? Here is my script below:

using (Geodatabase geodatabase = new Geodatabase(connection))
{
QueryDef queryDef = new QueryDef
{
Tables = "MUPOLYGON.Name",
SubFields = "MUPOLYGON.OBJECTID, MUPOLYGON.AREASYMBOL, MUPOLYGON.MUSYM, MUPOLYGON.MUKEY",
};

QueryTableDescription queryTableDescription = new QueryTableDescription(queryDef)
{
Name = "MUTable",
PrimaryKeys = geodatabase.GetSQLSyntax().QualifyColumnName("OBJECTID", "AREASYMBOL"),
};

Table queryTable = geodatabase.OpenQueryTable(queryTableDescription);

using (RowCursor rowCursor = queryTable.Search())
{
while (rowCursor.MoveNext())
{
using (var row = rowCursor.Current)
{
var county = Convert.ToString(row["AREASYMBOL"]);
var mukey = Convert.ToString(row["MUKEY"]);
if (MUResults.ContainsKey(county))
MUResults[county].Add(mukey);

....

Thanks for your help!

Re: QueryTable Error

GKmieliauskas — Wed, 08 Dec 2021 06:19:35 GMT

There is no declaration of MUResults. But as I understand from your code, your last code line must be like that:

MUResults[county]= mukey; // or MUResults.Add(county, mukey);

Re: QueryTable Error

Wolf — Wed, 08 Dec 2021 14:37:27 GMT

As @GKmieliauskas mentioned you forgot to include the declaration for MUResults. With the correct declaration your code can work:

var MUResults = new Dictionary<string, List<string>>(); MUResults.Add("County1", new List<string>() { "First Item for County 1" }); if (MUResults.ContainsKey("County1")) { MUResults["County1"].Add("Second Item for County 1"); }

Re: QueryTable Error

ThiPham12 — Sat, 11 Dec 2021 01:48:17 GMT

Thanks Wolf! I did add the dictionary declaration, but I didn't declare the value, mukey as a List.

I changed my dictionary declaration from "var MUResults = new Dictionary<string, <string>>();" to "var MUResults = new Dictionary<string, List<string>>();"

Once I changed the mukey declaration, I have the following error "cannot convert from string to System.Collection.Generic.List<string>." How can I resolve this error? Thanks for your help!

Re: QueryTable Error

KennyPham — Sun, 16 Jan 2022 11:37:25 GMT

Seem like the mukey is a string and not a list as declared in the dictionary.

@ThiPham12 wrote:
Thanks Wolf! I did add the dictionary declaration, but I didn't declare the value, mukey as a List.
I changed my dictionary declaration from "var MUResults = new Dictionary<string, <string>>();" to "var MUResults = new Dictionary<string, List<string>>();"
Once I changed the mukey declaration, I have the following error "cannot convert from string to System.Collection.Generic.List<string>." How can I resolve this error? Thanks for your help!

var mukey = Convert.ToString(row["MUKEY"]);

you have to know if the content in mukey column is a string or you want to have a list of item (so a list of string). I think just change the dictionary to new Dictionary<string, string> should be fine.

Re: QueryTable Error

Wolf — Wed, 26 Jan 2022 20:17:43 GMT

I used the community sample data for my code below, specifically the data in C:\Data\Admin\AdminData.gdb. Needless to say, i had to change the table names and field names. Here is the code for my sample button 'OnClick':

protected override async void OnClick() { try { var MUResults = new Dictionary<string, List<string>>(); var gdbFolder = @"C:\Data\Admin\AdminData.gdb"; var gdbPath = new FileGeodatabaseConnectionPath(new Uri(gdbFolder)); await QueuedTask.Run(() => { using (Geodatabase geodatabase = new Geodatabase(gdbPath)) { QueryDef queryDef = new QueryDef { Tables = "PopulationByCounty", SubFields = "OBJECTID, NAME, POP" }; QueryTableDescription queryTableDescription = new QueryTableDescription(queryDef) { Name = "PopulationByCounty", PrimaryKeys = geodatabase.GetSQLSyntax().QualifyColumnName("PopulationByCounty", "NAME") }; Table queryTable = geodatabase.OpenQueryTable(queryTableDescription); using (RowCursor rowCursor = queryTable.Search()) { while (rowCursor.MoveNext()) { using (var row = rowCursor.Current) { var county = row["NAME"].ToString(); var mukey = row["POP"].ToString(); if (MUResults.ContainsKey(county)) MUResults[county].Add(mukey); else MUResults.Add(county, new List<string>() { mukey }); } } } } }); foreach (var county in MUResults.Keys) { System.Diagnostics.Trace.WriteLine($@"County: {county}"); foreach (var mukey in MUResults[county]) { System.Diagnostics.Trace.WriteLine($@" MUKEY - {mukey}"); } } } catch (Exception ex) { MessageBox.Show(ex.Message); } }

And here some of the content (as output by my sample) for the dictionary:

County: Autauga County, Alabama
MUKEY - 54597
MUKEY - 54773
MUKEY - 54893
MUKEY - 55869
County: Baldwin County, Alabama
MUKEY - 182265
MUKEY - 183112
MUKEY - 199183
MUKEY - 223234
County: Barbour County, Alabama
MUKEY - 27455
MUKEY - 27327
MUKEY - 26755
MUKEY - 24686
County: Bibb County, Alabama
MUKEY - 22915
MUKEY - 22870
MUKEY - 22553
MUKEY - 22394