Sample code to update the value of a property's cell in a relationship grid.

labs_SetOwnerOnInsertRow.js

var set_property = setRelatedItemProperty(relationshipID, "owned_by_id", "DBA5D86402BF43D5976854B8B48FCDD1");

// At this point the value is set on the item in the dom, but it does not seem to appear in the grid
// By debugging into this function, the item also does not seem to be added to the grid at this point, so we'll need to handle this logic in a timeout
setTimeout(function(relID) {
    var gridApp = this.gridApplet;
    var columnName = gridApp.GetPropertyColumnName("owned_by_id");
    gridApp.SetCellValue(relID, gridApp.GetTrueColumnIndex(columnName), "Innovator Admin"); // <-- This should be the keyed_name of the item
}, 50, relationshipID);

/*
 * The column names in the grid are based on the property names, but don't match exactly. This function will figure
 * out the column name from the property name.
 */
gridApplet.GetPropertyColumnName = function(propName) {
    // All columns follow the format of "property_name" + "_Identifier". For example, the name of the quantity column is "quantity_D" with D
    // being an identifier for a digit. We want to strip out the "_Identifier" so we can compare directly with the property name
    var columnName = this.grid_Experimental.nameColumns.filter(function(colName) {
        var columnPropertyName = colName.substr(0, (colName.length - 2));
        return (columnPropertyName === propName);
    });

    return columnName[0] || "";
}

/*
 * We want to use gridApp.SetCellValue(rowId, colIndex); in order to set the value of the column in the grid.
 * 
 * Ideally, we could use gridApp.GetColumnIndex(columnName); to get the index of the column, but this actually returns an 
 * incorrect value in mixed-property grids like Part BOM. So we have to use a slightly-more involved method of getting the correct
 * column index.
 */
gridApplet.GetTrueColumnIndex = function(colName) 
{
    var wrongColumnIndex = this.GetColumnIndex(colName);
    var trueColumnOrder = this.grid_Experimental.order;

    // grid_Experimental.order contains a mapping between the wrong column indecies and the correct ones
    return trueColumnOrder.indexOf(wrongColumnIndex);
}