# SQLite Layer **URL:** \ **Category:** WinForms\ **Created:** [November 15, 2013, 6:26am UTC](https://community.thinkgeo.com/t/sqlite-layer/2319 "2013-11-15T06:26:17Z")\ **Posts on this page:** 9\ **Page:** 1
**Author:** ![Jonathan3](https://community.thinkgeo.com/letter_avatar_proxy/v4/letter/j/c68b51/32.png) [@Jonathan3](https://community.thinkgeo.com/u/Jonathan3)\ **Post date:** [November 15, 2013, 6:26am UTC](https://community.thinkgeo.com/t/sqlite-layer/2319/1 "2013-11-15T06:26:17Z")
Following on from an earlier discussion I have been trying out using SQLite for a custom layer (just lines and polygons at the moment).  I based my new layer on the example _ExtendingMapSuiteFeatureSource _and it works really well however my new layer does not appear to have a bounding box.  As a guess I tried overriding _GetBoundingBoxCore _in the new feature source class but that didn’t help as it doesn’t seem to get called from anywhere. Could you help me with setting the bounding box for my new layer? Regards, Jonathan ---
**Author:** ![Ethan](https://community.thinkgeo.com/user_avatar/community.thinkgeo.com/ethan/32/19964_2.png) [@Ethan](https://community.thinkgeo.com/u/Ethan)\ **Post date:** [November 18, 2013, 1:09am UTC](https://community.thinkgeo.com/t/sqlite-layer/2319/2 "2013-11-18T01:09:59Z")
Hi Jonathan,      Sorry I haven’t find original post, and if I misunderstand your question please let me know.      Do you meant you modify our sample ExtendingMapSuiteFeatureSource to render your layer, and your layer data is saved in SQLite.      This layer can be render well, but GetBoundingBox function don’t works, is that right?      Any sample or more exactly information should be helpful.      Regards,      Don ---
**Author:** ![Jonathan3](https://community.thinkgeo.com/letter_avatar_proxy/v4/letter/j/c68b51/32.png) [@Jonathan3](https://community.thinkgeo.com/u/Jonathan3)\ **Post date:** [November 18, 2013, 8:49am UTC](https://community.thinkgeo.com/t/sqlite-layer/2319/3 "2013-11-18T08:49:34Z")
Don, Your description is exactly right.  The layer renders well but get bounding box for the layer returns an error as the bounding box is not defined. The code for the feature source layer is: (Not I added the override to GetBoundingBoxCore as an attempt to fix the getBoundingBox error. > `using` `System;` > `using` `System.Collections.Generic;` > `using` `System.Collections.ObjectModel;` > `using` `System.Linq;` > `using` `System.Text;` > `using` `System.Data.SQLite;` > `using` `ThinkGeo.MapSuite.Core;` >   > `namespace` `PTSimpleMapper` > `{` > `    ``class` `clsPearFeatureSource : FeatureSource` > `    ``{` >   > `        ``private` `SQLiteConnection pearConnection = ``new` `SQLiteConnection();` >   > `        ``// Default constructor` > `        ``// Should chain to a more complex constructor when add more functionality` > `        ``public` `clsPearFeatureSource() { }` >   > `        ``// OVERRIDE STANDARD FUNCTIONS` >   > `        ``// Open core ` > `        ``protected` `override` `void` `OpenCore()` > `        ``{` > `            ``pearConnection = ``new` `SQLiteConnection(@``"Data Source=C:\Users\Jonathan\Documents\Visual Studio 2008\Projects\TestSQLite\TestSQLite\bin\Debug\myTestDB.db"``);` > `            ``pearConnection.Open();` > `        ``}` >   > `        ``// Close core` > `        ``protected` `override` `void` `CloseCore()` > `        ``{` > `            ``pearConnection.Close();` > `        ``}` >   > `        ``protected` `override` `Collection GetAllFeaturesCore(IEnumerable<``string``> returningColumnNames)` > `        ``{` >   > `            ``Collection rtn = ``new` `Collection();` > `            ``string` `theSQL = ``"SELECT Key, Value FROM Setting"``;` > `            ``SQLiteCommand getAllFeatures = ``new` `SQLiteCommand(theSQL, pearConnection);` >   > `            ``try` > `            ``{` > `                ``using` `(SQLiteDataReader reader = getAllFeatures.ExecuteReader())` > `                ``{` > `                    ``while` `(reader.Read())` > `                    ``{ rtn.Add(``new` `Feature(reader[``"Value"``].ToString())); }` > `                ``}` > `            ``}` > `            ``finally` > `            ``{` > `                ``if` `(!getAllFeatures.Equals(``null``)) { getAllFeatures.Dispose(); }` > `            ``}` >   > `            ``return` `rtn;` > `        ``}` >   > `        ``protected` `override` `Collection GetFeaturesInsideBoundingBoxCore(RectangleShape boundingBox, IEnumerable<``string``> returningColumnNames)` > `        ``{` >   > `            ``Collection rtn = ``new` `Collection();` > `            ``string` `theSQL = ``string``.Format(``"SELECT Key, Value FROM Setting WHERE"` > `                ``+ ``" NOT (LR_Y >= {0}) AND NOT (UL_Y <= {1}) AND NOT (LR_X <= {2}) AND NOT (UL_X >= {3})"``,` > `                ``boundingBox.UpperLeftPoint.Y,` > `                ``boundingBox.LowerRightPoint.Y,` > `                ``boundingBox.UpperLeftPoint.X,` > `                ``boundingBox.LowerRightPoint.X);` >   > `            ``SQLiteCommand getAllFeatures = ``new` `SQLiteCommand(theSQL, pearConnection);` >   > `            ``try` > `            ``{` > `                ``using` `(SQLiteDataReader reader = getAllFeatures.ExecuteReader())` > `                ``{` > `                    ``while` `(reader.Read())` > `                    ``{ rtn.Add(``new` `Feature(reader[``"Value"``].ToString())); }` > `                ``}` > `            ``}` > `            ``finally` > `            ``{` > `                ``if` `(!getAllFeatures.Equals(``null``)) { getAllFeatures.Dispose(); }` > `            ``}` >   > `            ``return` `rtn;` > `        ``}` >   > `        ``protected` `override` `RectangleShape GetBoundingBoxCore()` > `        ``{` >   > `            ``RectangleShape rtn = ``new` `RectangleShape();` >   > `            ``string``[] theSQL = ``new` `string``[4] {` > `                ``"SELECT MAX(UL_Y) FROM Settings"``,` > `                ``"SELECT MIN(LR_Y) FROM Settings"``,` > `                ``"SELECT MAX(LR_X) FROM Settings"``,` > `                ``"SELECT MIN(UL_X) FROM Settings"``};` >   > `            ``double``[] theLimits = ``new` `double``[4] { 0, 0, 0, 0 };` >   > `            ``try` > `            ``{` > `                ``theLimits[0] = Convert.ToInt32(``new` `SQLiteCommand(theSQL[0], pearConnection).ExecuteScalar());` > `                ``theLimits[1] = Convert.ToInt32(``new` `SQLiteCommand(theSQL[1], pearConnection).ExecuteScalar());` > `                ``theLimits[2] = Convert.ToInt32(``new` `SQLiteCommand(theSQL[2], pearConnection).ExecuteScalar());` > `                ``theLimits[3] = Convert.ToInt32(``new` `SQLiteCommand(theSQL[3], pearConnection).ExecuteScalar());` >   > `                ``PointShape ul = ``new` `PointShape(theLimits[4], theLimits[1]);` > `                ``PointShape lr = ``new` `PointShape(theLimits[3], theLimits[2]);` >   > `                ``rtn = ``new` `RectangleShape(ul, lr);` >   > `            ``}` > `            ``finally` > `            ``{` > `            ``}` >   > `            ``return` `rtn;` > `        ``}` >   > `        ``protected` `override` `int` `GetCountCore()` > `        ``{` > `            ``int` `rtn = 0;` > `            ``string` `theSQL = ``"SELECT COUNT(*) FROM Setting"``;` > `            ``SQLiteCommand getCount = ``new` `SQLiteCommand(theSQL, pearConnection);` >   > `            ``try` > `            ``{ ` > `                ``rtn = Convert.ToInt32(getCount.ExecuteScalar()); ` > `            ``}` > `            ``finally` > `            ``{` > `                ``if` `(!getCount.Equals(``null``)) { getCount.Dispose(); }` > `            ``}` >   > `            ``return` `rtn;` > `        ``}` >   > `    ``}` > `}` The error I get when trying "theMap.CurrentExtent = theOverlay.Layers.First().GetBoundingBox();" is: System.NotSupportedException was unhandled   Message="This Layer doesn’t have a boundingBox."   Source="MapSuiteCore"   StackTrace:        at ohM=.TFA=.ZVE=(Boolean ZlE=)        at ThinkGeo.MapSuite.Core.Layer.GetBoundingBox()        at PTSimpleMapper.clsProjectSupport.findFirstBoundingBox(WinformsMap& theMap, LayerOverlay& theOverlay) in C:\Users\Jonathan\Documents\Visual Studio 2008\Projects\simpleMapper\simpleMapper\MapProject\clsProjectSupport.cs:line 383        at PTSimpleMapper.clsProjectSupport.showFullExtent(WinformsMap& theMap, LayerOverlay& theOverlay) in C:\Users\Jonathan\Documents\Visual Studio 2008\Projects\simpleMapper\simpleMapper\MapProject\clsProjectSupport.cs:line 368        at PTSimpleMapper.clsProjectSupport.showFullExtent(WinformsMap& theMap) in C:\Users\Jonathan\Documents\Visual Studio 2008\Projects\simpleMapper\simpleMapper\MapProject\clsProjectSupport.cs:line 478        at PTSimpleMapper.frmMap.anyNavigationButton\_Click(Object sender, EventArgs e) in C:\Users\Jonathan\Documents\Visual Studio 2008\Projects\simpleMapper\simpleMapper\Forms and Dialogs\frmMap.cs:line 1103        at System.Windows.Forms.Control.OnClick(EventArgs e)        at System.Windows.Forms.Button.OnClick(EventArgs e)        at System.Windows.Forms.Button.OnMouseUp(MouseEventArgs mevent)        at System.Windows.Forms.Control.WmMouseUp(Message& m, MouseButtons button, Int32 clicks)        at System.Windows.Forms.Control.WndProc(Message& m)        at System.Windows.Forms.ButtonBase.WndProc(Message& m)        at System.Windows.Forms.Button.WndProc(Message& m)        at System.Windows.Forms.Control.ControlNativeWindow.OnMessage(Message& m)        at System.Windows.Forms.Control.ControlNativeWindow.WndProc(Message& m)        at System.Windows.Forms.NativeWindow.DebuggableCallback(IntPtr hWnd, Int32 msg, IntPtr wparam, IntPtr lparam)        at System.Windows.Forms.UnsafeNativeMethods.DispatchMessageW(MSG& msg)        at System.Windows.Forms.Application.ComponentManager.System.Windows.Forms.UnsafeNativeMethods.IMsoComponentManager.FPushMessageLoop(Int32 dwComponentID, Int32 reason, Int32 pvLoopData)        at System.Windows.Forms.Application.ThreadContext.RunMessageLoopInner(Int32 reason, ApplicationContext context)        at System.Windows.Forms.Application.ThreadContext.RunMessageLoop(Int32 reason, ApplicationContext context)        at System.Windows.Forms.Application.Run(Form mainForm)        at PTSimpleMapper.Program.Main() in C:\Users\Jonathan\Documents\Visual Studio 2008\Projects\simpleMapper\simpleMapper\Program.cs:line 18        at System.AppDomain.\_nExecuteAssembly(Assembly assembly, String[] args)        at System.AppDomain.ExecuteAssembly(String assemblyFile, Evidence assemblySecurity, String[] args)        at Microsoft.VisualStudio.HostingProcess.HostProc.RunUsersAssembly()        at System.Threading.ThreadHelper.ThreadStart\_Context(Object state)        at System.Threading.ExecutionContext.Run(ExecutionContext executionContext, ContextCallback callback, Object state)        at System.Threading.ThreadHelper.ThreadStart()   InnerException:  Regards, Jonathan ---
**Author:** ![Jonathan3](https://community.thinkgeo.com/letter_avatar_proxy/v4/letter/j/c68b51/32.png) [@Jonathan3](https://community.thinkgeo.com/u/Jonathan3)\ **Post date:** [November 18, 2013, 9:22am UTC](https://community.thinkgeo.com/t/sqlite-layer/2319/4 "2013-11-18T09:22:13Z")
I may have solved this one, but I would like to know if I’m going about it the right way?      In the featureLayer I did a simple override of HasBoundingBox to return TRUE.  This resulted in the FeatureSource function GetBoundingBoxCore being called.  There were a few errors in my code for this function but they were quite easy to fix.      Is it OK to simply return TRUS? or should I be doing some sort of check or something for HasBoundingBox?      Regards,   Jonathan ---
**Author:** ![Ethan](https://community.thinkgeo.com/user_avatar/community.thinkgeo.com/ethan/32/19964_2.png) [@Ethan](https://community.thinkgeo.com/u/Ethan)\ **Post date:** [November 19, 2013, 3:12am UTC](https://community.thinkgeo.com/t/sqlite-layer/2319/5 "2013-11-19T03:12:54Z")
Hi Jonathan,      I think you are right, as below is the description about HasBoundingBox:      This property indicates whether a Layer has a BoundingBox or not. If it has no BoundingBox, it will throw an exception when you call the GetBoundingBox() and GetFullExtent() APIs.      So just override HasBoundingBox is OK.        public override bool HasBoundingBox           {               get { return true; }           }      Regards,      Don  ---
**Author:** ![Jonathan3](https://community.thinkgeo.com/letter_avatar_proxy/v4/letter/j/c68b51/32.png) [@Jonathan3](https://community.thinkgeo.com/u/Jonathan3)\ **Post date:** [November 19, 2013, 5:32am UTC](https://community.thinkgeo.com/t/sqlite-layer/2319/6 "2013-11-19T05:32:45Z")
Don,      OK, thanks.  I did think I might put in one simple check and only return true for HasBoundingBox if the count of features is not zero.      All the best,   Jonathan ---
**Author:** ![Ethan](https://community.thinkgeo.com/user_avatar/community.thinkgeo.com/ethan/32/19964_2.png) [@Ethan](https://community.thinkgeo.com/u/Ethan)\ **Post date:** [November 20, 2013, 12:15am UTC](https://community.thinkgeo.com/t/sqlite-layer/2319/7 "2013-11-20T00:15:46Z")
Jonathan,      You can just return a new RectangleShape if the feature number is zero in GetBoundingBoxCore.      Regards,      Don ---
**Author:** ![Jonathan3](https://community.thinkgeo.com/letter_avatar_proxy/v4/letter/j/c68b51/32.png) [@Jonathan3](https://community.thinkgeo.com/u/Jonathan3)\ **Post date:** [November 20, 2013, 4:59am UTC](https://community.thinkgeo.com/t/sqlite-layer/2319/8 "2013-11-20T04:59:01Z")
Don,      Thank you, that makes good sense.      Regards,   Jonathan ---
**Author:** ![Ethan](https://community.thinkgeo.com/user_avatar/community.thinkgeo.com/ethan/32/19964_2.png) [@Ethan](https://community.thinkgeo.com/u/Ethan)\ **Post date:** [November 20, 2013, 8:45pm UTC](https://community.thinkgeo.com/t/sqlite-layer/2319/9 "2013-11-20T20:45:08Z")
Jonathan,      I am glad to know my reply helpful, any question please let us know.      Reagards,      Don