Question

I have problem with databinding in the Win.Forms DataGridView control.
Example:

public class A
{
      public String Title {get; set; }
      public B BField { get; set; }
}

public class B
{
      public String Name { get; set; }
}

I want to see in my column value from B. (BField.Name).
I tried to use the next way for data key, just fill with BField.Name value, but it doesn’t work for me. Else I want to have opportunity for chaning this field value via DataGridView.

Also I tried to create:

class A 
{
...

       public String BField_Name 
       {
           get{return BField.Name;} 
           set{BField.Name = value;}
       }
}

But it doesn’t work too.
Can you help me to fix this problem?

Thanks!

With The Best Regards,
Alexander.

Answer 1

To have the “B” class value show correctly in the Grid, override the ToString method to return the Title property.

You can then create a TypeConvertor for the “B” class so the Grid knows how to translate the string cell value into a “B” class type, i.e.

   public class BStringConvertor : TypeConverter
   {
      public BStringConvertor()
         : base()
      {
      }

      public override bool CanConvertFrom(ITypeDescriptorContext context, Type sourceType)
      {
         // Allow conversion from a String type
         if (sourceType == typeof(string))
            return true;

         return base.CanConvertFrom(context, sourceType);
      }

      public override object ConvertFrom(ITypeDescriptorContext context, System.Globalization.CultureInfo culture, object value)
      {
         // If the source value is a String, convert it to the "B" class type
         if (value is string)
         {
            B item = new B();
            item.Title = value.ToString();
            return item;
         }
         return base.ConvertFrom(context, culture, value);
      }

      public override object ConvertTo(ITypeDescriptorContext context, System.Globalization.CultureInfo culture, object value, Type destinationType)
      {
         // If the destination type is a String, convert the "B" class to a string
         if (destinationType == typeof(string))
            return value.ToString();

         return base.ConvertTo(context, culture, value, destinationType);
      }
   }

Then you can apply the converter to the “B” class property of your “A” class, i.e.

   public class A
   {
      public string Title { get; set; }

      [TypeConverter(typeof(BStringConvertor))]
      public B BField { get; set; }
   }

   public class B
   {
      public string Title { get; set; }

      public override string ToString()
      {
         return this.Title;
      }
   }