public string _LanguageField = null;
	[Browsable(false),
        Category("Post Settings"),
        WebPartStorage(Storage.Personal),
        FriendlyName("Language Field"),
        Description("Select the column to apply")]
        public string LanguageField
        {
            get
            {
                return _LanguageField;
            }
            set
            {
                _LanguageField = value;
            }
        }
        
		

public enum DemoList
        {
            Une = 1,
            Deux = 2,
            Trois = 3,
            Quatre = 4
        };
        protected DemoList _DemoListValues;
        
        [Category("Post Settings")]
        [DefaultValue(DemoList.Deux)]
        [WebPartStorage(Storage.Personal)]
        [FriendlyName("Example")]
        [Description("Select a value")]
        [Browsable(true)]
        public DemoList DemoListValues
        {
            get
            {
                return _DemoListValues;
            }
            set
            {
                _DemoListValues = value;
            }
        }

private IWebPartField LanguageProvider; //Will point to the provider
private object ProvidedLanguageValue;//Will hold the value provided by the provider

private void GetFieldValue(object fieldValue)
        {
            ProvidedLanguageValue = fieldValue;
        }
        
        [ConnectionConsumer("FieldConsumer", "LanguageConnectionPoint",
      typeof(FieldConsumerConnectionPoint), AllowsMultipleConnections = false)]
        public void SetConnectionInterface(IWebPartField provider)
        {
            LanguageProvider = provider;
        }
        protected override void OnPreRender(EventArgs e)
        {
            if (LanguageProvider != null)
            {
                LanguageProvider.GetFieldValue(new FieldCallback(GetFieldValue));
            }
            base.OnPreRender(e);
        }

public class FieldConsumerConnectionPoint : ConsumerConnectionPoint
    {
        public FieldConsumerConnectionPoint(MethodInfo callbackMethod,
          Type interfaceType, Type controlType, string name, string id,
          bool allowsMultipleConnections)
            : base(
          callbackMethod, interfaceType, controlType,
          name, id, allowsMultipleConnections)
        {
        }
        
    }
    

SPQuery PostQuery = new SPQuery();
//that query retrieves all the items sorted descendingly on the creation date
PostQuery.Query = "<OrderBy><FieldRef Name=\"Created\" Ascending=\"FALSE\" /></OrderBy>";
if (LanguageField != null)
{
    PropertyDescriptor prop = LanguageProvider.Schema;
    //If the value provided value isn't null, I create an SPQuery that takes the provided value into account.
    if (prop != null && ProvidedLanguageValue != null && ProvidedLanguageValue.ToString().ToLower() != "no filter")
    {
       StringBuilder SpQueryString = new StringBuilder();
       SpQueryString.Append("&lt;OrderBy>&lt;FieldRef Name=\"Created\" Ascending=\"FALSE\" />&lt;/OrderBy>");
       SpQueryString.AppendFormat("&lt;Where>&lt;Eq>&lt;FieldRef Name='{0}' />&lt;Value Type='Text'>{1}&lt;/Value>&lt;/Eq>&lt;/Where>",
              PostList.Fields[LanguageField].InternalName,//Must use the internal name in CAML queries
              ProvidedLanguageValue //contains the value provided by the provider   
       );
       PostQuery.Query = SpQueryString.ToString();
    }                        
}

foreach (SPListItem PostItem in PostList.GetItems(PostQuery))
{
    HtmlTable ItemTable = new HtmlTable();
    HtmlTableRow ItemRow = new HtmlTableRow();
    HtmlTableCell ItemCell = new HtmlTableCell();
       .....//d'autres lignes
	if (ExpandedEnabled)
    {
        //If the expanding/collapsing functionality has been activated, I just add an image next to each post title
        TitleCellHtml.Append("<img onclick=\"if(this.src.indexOf('minus') != -1){");
        TitleCellHtml.Append("this.parentNode.parentNode.parentNode.rows[1].style.display='none';");
        TitleCellHtml.Append("this.src='_layouts/images/plus.gif';}");
        TitleCellHtml.Append("else{this.parentNode.parentNode.parentNode.rows[1].style.display='';");
        TitleCellHtml.Append("this.src='_layouts/images/minus.gif';}\" src='_layouts/images/minus.gif'/>&nbsp;");
    }                    
       .....//d'autres lignes					
}

using System;
using System.Collections.Generic;
using System.Text;
using System.Web.UI;
using System.Web.UI.WebControls;
using Microsoft.SharePoint;
using Microsoft.SharePoint.WebPartPages;

namespace MultiLingualPost
{
    class FieldList : Microsoft.SharePoint.WebPartPages.ToolPart
    {
        MultiLingualPost ParentWp = null;
        Label ErrorMessage = null;
        public FieldList()
        {
            this.Title = "Language Field";
        }
        public override void ApplyChanges()
        {
            string FieldName = Page.Request.Form["LanguageField"];
            ParentWp = (MultiLingualPost)this.ParentToolPane.SelectedWebPart;
            ParentWp.LanguageField = FieldName;
        }
        protected override void CreateChildControls()
        {
            ErrorMessage = new Label();
            ErrorMessage.Style.Add(HtmlTextWriterStyle.Color, "red");
            this.Controls.Add(ErrorMessage);
        }
        /// <summary>
        ///	If the ApplyChanges method succeeds, this method is called by the tool pane 
        ///	to refresh the specified property values in the toolpart user interface.
        /// </summary>
        public override void SyncChanges()
        {
            // sync with the new property changes here
        }

        /// <summary>
        ///	Called by the tool pane if the user discards changes to the selected Web Part. 
        /// </summary>
        public override void CancelChanges()
        {
        }
        
        protected override void RenderToolPart(HtmlTextWriter output)
        {
			//LanguageField is a HTML list that will contain all the columns belonging to the "Post" list.
            ParentWp = (MultiLingualPost)this.ParentToolPane.SelectedWebPart;
            output.Write("<select name='LanguageField'>");
            try
            {
                
				//Getting the columns of the "Posts" list 
                foreach (SPField ListField in SPContext.Current.Web.Lists["Posts"].Fields)
                {
                    
                        if (ParentWp.LanguageField != ListField.Title)
                        {
                            output.Write("<option>" + ListField.Title + "</option>");
                        }
                        else
                        {
                            output.Write("<option selected>" + ListField.Title + "</option>");
                        }
                    
                }

            }
            catch (Exception e)
            {
                ErrorMessage.Text = e.Message;
            }

            output.Write("</select>");
            ErrorMessage.RenderControl(output);
        }
    }
}

public override ToolPart[] GetToolParts()
        {
            ToolPart[] toolparts = new ToolPart[3];
            WebPartToolPart wptp = new WebPartToolPart();
            CustomPropertyToolPart custom = new CustomPropertyToolPart();
            toolparts[0] = custom;
            toolparts[1] = wptp;            
            toolparts[2] = new FieldList(); //Language field is called from here
            return toolparts;
        }

<select name="language" onchange="javascript:_SFSUBMIT_"/><option>No Filter</option><option>FR</option><option>EN</option></select>