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POSystem.MissingMethodException: Cannot create an instance of an interface
 

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    <p>I have a form that has a few text boxes, you input some values into the text boxes and then when you press submit it saves the values to a file. However when I press submit, I get the following exception. I've narrowed the problem down to something in the InventoryMngr and CreateInventory code, but I am unsure what I am doing wrong there.</p> <pre><code>System.MissingMethodException: Cannot create an instance of an interface. at HomeInventory2.Services.Factory.GetService(String servicename) in C:\Users\Protego\documents\visual studio 2010\Projects\HomeInventory2\HomeInventory2\Services\Factory.cs:line 37 at HomeInventory2.Business.Manager.GetService(String name) in C:\Users\Protego\documents\visual studio 2010\Projects\HomeInventory2\HomeInventory2\Business\Manager.cs:line 14 at HomeInventory2.Business.InventoryMngr.Create(CreateInventory inv) in C:\Users\Protego\documents\visual studio 2010\Projects\HomeInventory2\HomeInventory2\Business\InventoryMngr.cs:line 19 at HomeInventory2.Form1.submitButton_Click(Object sender, EventArgs e) in C:\Users\Protego\documents\visual studio 2010\Projects\HomeInventory2\HomeInventory2\Form1.cs:line 52 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&amp; m, MouseButtons button, Int32 clicks) at System.Windows.Forms.Control.WndProc(Message&amp; m) at System.Windows.Forms.ButtonBase.WndProc(Message&amp; m) at System.Windows.Forms.Button.WndProc(Message&amp; m) at System.Windows.Forms.Control.ControlNativeWindow.OnMessage(Message&amp; m) at System.Windows.Forms.Control.ControlNativeWindow.WndProc(Message&amp; m) at System.Windows.Forms.NativeWindow.Callback(IntPtr hWnd, Int32 msg, IntPtr wparam, IntPtr lparam) </code></pre> <p>InventoryMngr</p> <pre><code>namespace HomeInventory2.Business { public class InventoryMngr : Manager { /// &lt;summary&gt; /// persists the inventory information /// &lt;/summary&gt; /// &lt;param name="inv"&gt;&lt;/param&gt; public void Create(CreateInventory inv) { InventorySvc inventorySvc = (InventorySvc)GetService(typeof(InventorySvc).Name); inventorySvc.CreateInventory(inv); } } } </code></pre> <p>CreateInventory</p> <pre><code>namespace HomeInventory2.Domain { [Serializable] public class CreateInventory { /// &lt;summary&gt; /// item category /// &lt;/summary&gt; private string itemCategory; public String ItemCategory { set { itemCategory = value; } get { return itemCategory; } } /// &lt;summary&gt; /// item properties /// &lt;/summary&gt; private string itemProperties; public String ItemProperties { set { itemProperties = value; } get { return itemProperties; } } /// &lt;summary&gt; /// item amount /// &lt;/summary&gt; private string itemAmount; public String ItemAmount { set { itemAmount = value; } get { return itemAmount; } } /// &lt;summary&gt; /// item value /// &lt;/summary&gt; private string itemValue; public String ItemValue { set { itemValue = value; } get { return itemValue; } } } } </code></pre> <p>InventorySvc is an interface</p> <pre><code>namespace HomeInventory2.Services { public interface InventorySvc : IService { void CreateInventory(CreateInventory createinventory); } } </code></pre> <p>InventoryImpl</p> <pre><code>namespace HomeInventory2.Services { public class InventoryImpl: InventorySvc { /// &lt;summary&gt; /// Creates an output files with the given inventory information written to it, serves as placeholder - this will be replaced with a database system /// &lt;/summary&gt; /// &lt;param name="createinventory"&gt;&lt;/param&gt; public void CreateInventory(CreateInventory createinventory) { try { FileStream fileStream = new FileStream ("CreateInventory.bin", FileMode.Create, FileAccess.Write); IFormatter formatter = new BinaryFormatter(); formatter.Serialize(fileStream, createinventory); fileStream.Close(); } catch (ItemNotFoundException) { throw new ItemNotFoundException("Output not created - see logs"); } } } } </code></pre>
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    1. COis InventorySvc an interface?
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    2. COwhat GetService does,can you show the code.Is InventorySvc an interface
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      1. USPrabhu Murthy
 

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