// FieldValueAtIndex
//
// PURPOSE: This function determines the value of a named field within some row within
// this DataSet. The tricky part is determining which row is desired. Consider an
// example. Suppose we have a page containing 3 DataSets: ds1, ds2 and ds3. This
// page might contain a DataGrid, g1, bound to ds1. Within the DataGrid may be
// with a TemplateColumn containing a Repeater, r1, bound to ds2. Within the Repeater
// might be an ItemTemplate containing ds1.FieldValue("foo", Container) as well as
// ds2.FieldValue("bar", Container). Outside the whole DataGrid might be another
// Repeater, r2, bound to ds1 containing an ItemTemplate containing
// ds1.FieldValue("foo", Container) and ds3.FieldValue("xyz", Container). We can
// diagram this as:
//
// DataSet ds1
// DataSet ds2
// DataSet ds3
//
// DataGrid g1 bound to ds1
// TemplateColumn
// ItemTemplate
// Repeater r1 bound to ds2
// ItemTemplate
// ds1.FieldValue("foo", Container) [use the row in ds1 that g1 is currently processing]
// ds2.FieldValue("bar", Container) [use the row in ds2 that r1 is currrently processing]
//
// Repeater r2 bound to ds1
// ds1.FieldValue("foo", Container) [use the row in ds1 that r2 is currently processing]
// ds3.FieldValue("xyz", Container) [use the 0th row in ds3]
//
// The challenge presented to this method is to resolve the field values according to the
// description shown above in square brackets.
//
public string FieldValueAtIndex(int Index, string FieldName, System.Web.UI.Control Container)
{
string strReturn = ""; // contains the field value that we eventually resolve to
try
{
// Make some objects so we can get their types to use later in comparisons.
System.Web.UI.WebControls.Repeater theRepeater = new System.Web.UI.WebControls.Repeater();
System.Web.UI.WebControls.DataList theDataList = new System.Web.UI.WebControls.DataList();
System.Web.UI.WebControls.DataGrid theDataGrid = new System.Web.UI.WebControls.DataGrid();
System.Web.UI.WebControls.RepeaterItem repeaterItemContainer = new System.Web.UI.WebControls.RepeaterItem(0, ListItemType.Item);
System.Web.UI.WebControls.DataListItem dataListItemContainer = new System.Web.UI.WebControls.DataListItem(0, ListItemType.Item);
System.Web.UI.WebControls.DataGridItem dataGridItemContainer = new System.Web.UI.WebControls.DataGridItem(0, 0, ListItemType.Item);
Type repeaterType = theRepeater.GetType();
Type dataListType = theDataList.GetType();
Type dataGridType = theDataGrid.GetType();
Type repeaterItemType = repeaterItemContainer.GetType();
Type dataListItemType = dataListItemContainer.GetType();
Type dataGridItemType = dataGridItemContainer.GetType();
theRepeater = null;
theDataList = null;
theDataGrid = null;
// We will now figure out what control (Repeater, DataList or DataGrid) this DataSet
// has been bound to. Later we can figure out what row that control is presently
// processing.
Control theParent = null;
if (Container != null)
{
theParent = Container.Parent;
while (theParent != null)
{
if (repeaterType.IsInstanceOfType(theParent))
{
theRepeater = (System.Web.UI.WebControls.Repeater)theParent;
if (theRepeater.DataSource == this.DefaultView)
{
break;
}
}
else if (dataListType.IsInstanceOfType(theParent))
{
theDataList = (System.Web.UI.WebControls.DataList)theParent;
if (theDataList.DataSource == this.DefaultView)
{
break;
}
}
else if (dataGridType.IsInstanceOfType(theParent))
{
theDataGrid = (System.Web.UI.WebControls.DataGrid)theParent;
if (theDataGrid.DataSource == this.DefaultView)
{
break;
}
}
theParent = theParent.Parent;
}
// Finding the control that this DataSet is bound to isn't enough.
// We have to get the field value of a the right record within
// that DataSet. That is, we have to find the row in that DataSet
// that the Repeater or DataList or DataGrid is currently processing.
if (theParent != null)
{
Control candidateBindingContainer = Container;
while (candidateBindingContainer != null)
{
while ((candidateBindingContainer == null) ||
((!repeaterItemType.IsInstanceOfType(candidateBindingContainer)) &&
(!dataListItemType.IsInstanceOfType(candidateBindingContainer)) &&
(!dataGridItemType.IsInstanceOfType(candidateBindingContainer))))
{
try
{
candidateBindingContainer = candidateBindingContainer.BindingContainer;
}
catch
{
candidateBindingContainer = null;
}
}
if (candidateBindingContainer != null)
{
if (repeaterType.IsInstanceOfType(theParent))
{
if ((candidateBindingContainer.Parent != null) &&
(candidateBindingContainer.Parent == theRepeater))
{
strReturn = ((DataView)(theRepeater.DataSource))[((RepeaterItem)candidateBindingContainer).ItemIndex][FieldName].ToString();
return strReturn;
}
}
else if (dataListType.IsInstanceOfType(theParent))
{
if ((candidateBindingContainer.Parent != null) &&
(candidateBindingContainer.Parent == theDataList))
{
strReturn = ((DataView)(theDataList.DataSource))[((DataListItem)candidateBindingContainer).ItemIndex][FieldName].ToString();
return strReturn;
}
}
else if (dataGridType.IsInstanceOfType(theParent))
{
if ((candidateBindingContainer.Parent != null) &&
(candidateBindingContainer.Parent.Parent != null) &&
(candidateBindingContainer.Parent.Parent == theDataGrid))
{
strReturn = ((DataView)(theDataGrid.DataSource))[((DataGridItem)candidateBindingContainer).ItemIndex][FieldName].ToString();
return strReturn;
}
}
candidateBindingContainer = candidateBindingContainer.Parent;
}
}
}
}
// If we haven't found the parent control then we must fall back on something
// safe: simply access the field value at the given index.
if (theParent == null)
{
strReturn = DefaultView[Index][FieldName].ToString();
}
}
catch
{
}
return strReturn.Trim();
}
