Code:
using System;
using System.Collections;
using System.ComponentModel;
using System.Security.Permissions;
using System.Web;
using System.Web.UI;
using System.Web.UI.WebControls;
namespace Samples.AspNet.Controls.CS {
[AspNetHostingPermission(SecurityAction.Demand,
Level=AspNetHostingPermissionLevel.Minimal)]
[AspNetHostingPermission(SecurityAction.InheritanceDemand,
Level=AspNetHostingPermissionLevel.Minimal)]
public class TextBoxSet : DataBoundControl {
private IList alBoxSet;
public IList BoxSet {
get {
if (null == alBoxSet) {
alBoxSet = new ArrayList();
}
return alBoxSet;
}
}
public string DataTextField {
get {
object o = ViewState["DataTextField"];
return((o == null) ? string.Empty : (string)o);
}
set {
ViewState["DataTextField"] = value;
if (Initialized) {
OnDataPropertyChanged();
}
}
}
protected override void PerformSelect() {
// Call OnDataBinding here if bound to a data source using the
// DataSource property (instead of a DataSourceID), because the
// databinding statement is evaluated before the call to GetData.
if (! IsBoundUsingDataSourceID) {
OnDataBinding(EventArgs.Empty);
}
// The GetData method retrieves the DataSourceView object from
// the IDataSource associated with the data-bound control.
GetData().Select(CreateDataSourceSelectArguments(),
OnDataSourceViewSelectCallback);
// The PerformDataBinding method has completed.
RequiresDataBinding = false;
MarkAsDataBound();
// Raise the DataBound event.
OnDataBound(EventArgs.Empty);
}
private void OnDataSourceViewSelectCallback(IEnumerable retrievedData) {
// Call OnDataBinding only if it has not already been
// called in the PerformSelect method.
if (IsBoundUsingDataSourceID) {
OnDataBinding(EventArgs.Empty);
}
// The PerformDataBinding method binds the data in the
// retrievedData collection to elements of the data-bound control.
PerformDataBinding(retrievedData);
}
protected override void PerformDataBinding(IEnumerable retrievedData) {
base.PerformDataBinding(retrievedData);
// If the data is retrieved from an IDataSource as an
// IEnumerable collection, attempt to bind its values to a
// set of TextBox controls.
if (retrievedData != null) {
foreach (object dataItem in retrievedData) {
TextBox box = new TextBox();
// The dataItem is not just a string, but potentially
// a System.Data.DataRowView or some other container.
// If DataTextField is set, use it to determine which
// field to render. Otherwise, use the first field.
if (DataTextField.Length > 0) {
box.Text = DataBinder.GetPropertyValue(dataItem,
DataTextField, null);
}
else {
PropertyDescriptorCollection props =
TypeDescriptor.GetProperties(dataItem);
// Set the "default" value of the TextBox.
box.Text = String.Empty;
// Set the true data-bound value of the TextBox,
// if possible.
if (props.Count >= 1) {
if (null != props[0].GetValue(dataItem)) {
box.Text = props[0].GetValue(dataItem).ToString();
}
}
}
BoxSet.Add(box);
}
}
}
protected override void Render(HtmlTextWriter writer) {
// Render nothing if the control is empty.
if (BoxSet.Count <= 0) {
return;
}
// Make sure the control is declared in a form tag
// with runat=server.
if (Page != null) {
Page.VerifyRenderingInServerForm(this);
}
// For this example, render the BoxSet as
// an unordered list of TextBox controls.
writer.RenderBeginTag(HtmlTextWriterTag.Ul);
foreach (object item in BoxSet) {
TextBox box = (TextBox) item;
// Write each element as
// <li><input type="text" value="string"><input/></li>
writer.WriteBeginTag("li");
writer.Write(">");
writer.WriteBeginTag("input");
writer.WriteAttribute("type", "text");
writer.WriteAttribute("value", box.Text);
writer.Write(">");
writer.WriteEndTag("input");
writer.WriteEndTag("li");
}
writer.RenderEndTag();
}
}
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