Public Property DataItemDataField As String

Dim instance As TagCloudCellType
Dim value As String
 
instance.DataItemDataField = value
 
value = instance.DataItemDataField

public string DataItemDataField {get; set;}

private DataSet CreateData()
{
    DataSet ds = new DataSet();
    DataTable dt = new DataTable();
    dt.Columns.Add(new DataColumn("ID", Type.GetType("System.Int32")));
    dt.Columns.Add(new DataColumn("Keyword", Type.GetType("System.String")));
    dt.Columns.Add(new DataColumn("Weight", Type.GetType("System.Int32")));

    dt.Rows.Add(new object[] { 1, ".net", 52 });
    dt.Rows.Add(new object[] { 2, "ajax", 22 });
    dt.Rows.Add(new object[] { 3, "css", 34 });

    ds.Tables.Add(dt);
    return ds;
} 
protected void Page_Load(object sender, EventArgs e)
{
    if (IsPostBack) return;

    TagCloudCellType tcloud = new TagCloudCellType();
    tcloud.DataSource = CreateData();
    tcloud.DataDisplayTextField = "Keyword";
    tcloud.DataHrefField = "Keyword";
    tcloud.DataHrefFormatString = "http://msdn.microsoft.com/en-us/library/Tags-Cloud.aspx?tag={0}";
    tcloud.DataWeightField = "Weight";
    tcloud.DataTitleField = "Weight";
    tcloud.DataTitleFormatString = "{0} item(s) tagged";
    tcloud.DataItemDataField = "ID";

    FpSpread1.Sheets[0].Cells[1, 1].CellType = tcloud; 
}
protected void Button1_Click(object sender, EventArgs e)
{
    TagCloudCellType tc = FpSpread1.Sheets[0].GetCellType(1, 1) as TagCloudCellType;
    foreach (TagCloudItem ci in tc.TagCloudItems)
    {
        // get the ItemData value associated to the cloud item 
        System.Diagnostics.Debug.WriteLine(string.Format("DisplayText:{0} , ItemValue:{1}", ci.DisplayText, ci.ItemData));
    } 
}

Private Function CreateData() As DataSet
    Dim ds As New DataSet
    Dim dt As New DataTable
    dt.Columns.Add(New DataColumn("ID", Type.GetType("System.Int32")))
    dt.Columns.Add(New DataColumn("Keyword", Type.GetType("System.String")))
    dt.Columns.Add(New DataColumn("Weight", Type.GetType("System.Int32")))

    dt.Rows.Add(New Object() {1, ".net", 52})
    dt.Rows.Add(New Object() {2, "ajax", 22})
    dt.Rows.Add(New Object() {3, "css", 34})

    ds.Tables.Add(dt)
    Return ds
End Function

Protected Sub Page_Load(ByVal sender As Object, ByVal e As System.EventArgs) Handles Me.Load
    If IsPostBack Then Return

    Dim tcloud As New TagCloudCellType
    tcloud.DataSource = CreateData()
    tcloud.DataDisplayTextField = "Keyword"
    tcloud.DataHrefField = "Keyword"
    tcloud.DataHrefFormatString = "http://msdn.microsoft.com/en-us/library/Tags-Cloud.aspx?tag={0}"
    tcloud.DataWeightField = "Weight"
    tcloud.DataTitleField = "Weight"
    tcloud.DataTitleFormatString = "{0} item(s) tagged"
    tcloud.DataItemDataField = "ID"

    FpSpread1.Sheets(0).Cells(1, 1).CellType = tcloud
End Sub

Protected Sub Button1_Click(ByVal sender As Object, ByVal e As System.EventArgs) Handles Button1.Click
    Dim tc As TagCloudCellType = FpSpread1.Sheets(0).GetCellType(1, 1)
    For Each ci As TagCloudItem In tc.TagCloudItems
        ' get the ItemData value associated to the cloud item
        System.Diagnostics.Debug.WriteLine(String.Format("DisplayText:{0} , ItemValue:{1}", ci.DisplayText, ci.ItemData))
    Next
End Sub