title: cannot convert from 'method group' to 'System.EventHandler'
body: <p>Hello StackOverflow community,</p>
  
  <p>I am working on a .NET windows application in c# and rebuilt one library project to two, as I want to use some classes in another project.</p>
  
  <p>However since my change I get an error as: cannot convert from 'method group' to 'System.EventHandler', when compiling. From a class / method which has always worked.</p>
  
  <p>The application is a complex mapping application which roles out an xml / xsd mapping with objects, parent and sub relationships, default values, list objects and additional features based on automatically read CRM and Webservice WSDL information.</p>
  
  <p>The following line gives the error: "mappingPickListControls = new MappingPickListControls(pMappingPickList, optionMetadataCollection, ValidationRegister, imglblMandatory, tbControlToValidate_validating);"</p>
  
  <p>The eventhandler is given to the control builders to ensure the method can be called by the correct control to validate the correct information.</p>
  
  <p><strong>CRMMappingPickListForm:</strong></p>
  
  <pre><code>private void tbControlToValidate_validating(object sender, CancelEventArgs e)
      {
          ValidateControl(this, (Control)sender);
      }
  
  public CRMMappingPickListForm(Ciber.Crm.MappingCRMTo.Data.CustomOptionMetadataCollection optionMetaDataCol, Point location, Size size)
      {
          InitializeComponent();
          this.Location = new Point (location.X + (size.Width / 2) - (Size.Width / 2), location.Y + (size.Height / 2) - (Size.Height / 2));
          optionMetadataCollection = optionMetaDataCol;
  
          ValidationRegister = new FormValidationRegister();
          ValidationRegister.ControlValidationRegister.Add(new ControlValidation("tbConfigurationName", 1, "configuration name", 1));
          mappingPickListControls = new MappingPickListControls(pMappingPickList, optionMetadataCollection, ValidationRegister, imglblMandatory, tbControlToValidate_validating);
      }
  </code></pre>
  
  <p><strong>MappingPickListControls:</strong></p>
  
  <pre><code>public MappingPickListControls(Panel pMappingPickList, CustomOptionMetadataCollection optionMetaDataCol, FormValidationRegister ValidationRegister, Bitmap imglblMandatory, EventHandler tbControlToValidate_validating) 
      {
          lblPickListValueList = new List&lt;Label&gt;();
          tbPickListMappedValueList = new List&lt;TextBox&gt;();
          foreach (CustomOptionMetadata optionMetaData in optionMetaDataCol)
          {
              AddMapping(pMappingPickList, optionMetaData, ValidationRegister, imglblMandatory, tbControlToValidate_validating);
          }
      }
  </code></pre>
  
  <p>I got 3 projects in my solution:</p>
  
  <p>MappingCRMTo: Has all the windows forms including the <strong>CRMMappingPickListFOrm</strong>
  MappingCRMTo.Controls: Has all the form extensions and form related classes. This is the new project library I created. It also includes <strong>MappingPickListControls</strong>, which is one of the control builder classes.
  MappingCRMTo.Data: Has all serialization objects, WSDL reader, zip creator and other classes I like to use throughout some other projects. It is the <em>old</em> location of <strong>MappingPickListControls</strong></p>