QueryTask

ToddMcNeil1

I have an asp.net page with a map and two controls.  One control selects a state, populates the second control with the counties within that selected state.  I select multiple counties and hit a button.  The button fires of a javascript function, loopSelected(), to loop through the selected counties and create an array.

function loopSelected() {
    //Define an array to store selected counties
    var selectedArray = new Array();
    var selObj = document.getElementById('countyListBox');
    var i;
    var count = 0;
    for (i = 0; i < selObj.options.length; i++) {
        if (selObj.options.selected) {
            selectedArray[count] = selObj.options.value;
            count++;
        }
    }
    //Pass array to Query and Find functions
    runCountyQuery(selectedArray);
    doCountyFind();
}

The selectedArray is passed to another function, runCountyQuery, that performs the QueryTask to select the multiple counties.

function runCountyQuery(selectedArray) {

    //Define a new Query and QueryTask
    queryTask = new esri.tasks.QueryTask("http://hwvanad1287/ArcGIS/rest/services/tdat/Acs/MapServer/0");

    //Create query parameters
    query = new esri.tasks.Query();
    query.returnGeometry = true;
    query.outFields = ["*"];

    //Parse selectedArray for query.where clause
    var strText;
    var i;
    var count = 0;
    for (i = 0; i < selectedArray.length; i++) {
        strText = selectedArray;
        alert('strText[' + i + ']: ' + strText);
        count++;
    }

    //This section actually runs the query. It's called by the loopSelected() function above.
    //The query is run as a deferred process, and the results are returned to the showQueryResults function.

    //The query's where clause is specified in the input field.
    //query.where = document.getElementById("countyListBox").value;
    //query.where = "GEOID = " + "'" + query.where + "'";
    //query.where = "GEOID IN (" + "'13001','13003','13005'" + ")";
    query.where = "GEOID IN (" + selectedArray + ")";
    alert('query.where:' + query.where);
    queryTask.execute(query, showQueryResults, errResults);
}

My problem is building the proper syntax for the query.where clause from the selectedArray.  I would also like to find the easiest way to debug the results on execute.  If there is an easier way to construct a query.where clause containing multiple values, I am all ears.

Todd McNeil
Geographer

U.S. Department of Housing and Urban Development
Office of Policy Development and Research

ToddMcNeil1

hzhu,

For one thing, I am adding two Feature Layers to the map, state and county.  So I can read up on the querying and selecting through the samples.

What if I keep going in the same direction that I have been?  Is it still possible to do what I need or is it worth the time to use the Feature Layer methods and properties instead?

Thanks!

Todd