wiki:CodeSamples/JavaScript/InvokeCommandOnStartup

    1. Overview

This page is one of the MapGuide Community CodeSamples. Visit the CodeSamples page to view more!

Overview

This html page can automatically invoke a named viewer command on viewer startup based on the value of a Cmd query string property. This uses the InitialTask property of the Web Layout.

For example setting this initial task pane url: 

http://path/to/autostart.html?Cmd=Measure

Will launch the Measure command on viewer startup.

As you can see from the code below, we need to employ initialization checks ​just like in the event hooking example, to make sure we can start using the Viewer API when the frames have been fully initialized.

autostart.html 

<html>
        <head>
                <title>Auto-start command in task pane</title>
                <script type="text/javascript">
                        
                        var viewerFrame = parent.parent;
                        
                        function GetQueryStringValue(key)
                        {
                                key = key.replace(/[\[]/,"\\\[").replace(/[\]]/,"\\\]");
                                var regex = new RegExp("[\\?&]"+key+"=([^&#]*)");
                                var qs = regex.exec(window.location.href);
                                if(qs == null)
                                        return "";
                                else
                                        return qs[1];
                        }
                        
                        function GetCommandIndex(name)
                        {
                                var cmds = viewerFrame.GetCommands();
                                for(var i = 0; i < cmds.length; i++)
                                {
                                        //This command array is not sequential, there may be holes
                                        //so we have to test element existence before testing name equality
                                        if (cmds[i] && cmds[i].name == name)
                                                return i;
                                }
                                return -1;
                        }
                        
                        function OnMapInitialized()
                        {
                                var cmdName = GetQueryStringValue("Cmd");
                                var i = GetCommandIndex(cmdName);
                                if (i < 0)
                                        alert("Command not found: " + cmdName);
                                else
                                        viewerFrame.ExecuteCommand(i);
                        }
                        
                        window.onload = function() {
                                //Timer variable
                                var timer; 

                                // This is our "watch" function. What we are doing here is 
                                // repeatedly checking the mapInit value of the Map Frame. When
                                // mapInit is true, then the map has been loaded.
                                var watch = function() {
                                        
                                        // What we are doing here is attempting to access the mapInit
                                        // variable of the Map frame. The reason the code is in a try-catch
                                        // is because chances are that this code access the DOM
                                        // of the map frame before its DOM has been initialized.
                                        try {
                                                var mapFrame = viewerFrame.mapFrame;
                                                if(mapFrame.mapInit) {
                         
                                                        // Remove the timer so this watch function stops executing
                                                        clearInterval(timer);
                                                         
                                                        // Call our custom handler
                                                        OnMapInitialized();
                                                }
                                        }
                                        catch(e) {
                                        }
                                };
                                
                                // Start the "watching" process. We basically invoke the watch function 
                                // every 200ms until the map has been loaded.
                                timer = setInterval(watch, 200);

                        };
                        
                </script>
        </head>
        <body>
        </body>
</html>
Last modified 12 years ago Last modified on 02/06/13 13:08:10
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