02/08/2011, 03:06
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| | | Fecha de Ingreso: julio-2011
Mensajes: 3
Antigüedad: 12 años, 9 meses Puntos: 0 | |
 Respuesta: Rellenar un TextBox al cambiar DropDownList median un DataSet
Gracias por la respuesta othix, pero lo que buscaba es algo más elaborado. al final he dado con la solución indagando en el manual AJAX with ASP.NET. El ejemplo que me ha servido de ejemplo para solucionar lo que os cuento es el siguiente:
Código del lado del servidor:
Código:
using System;
using System.Data;
using System.Configuration;
using System.Collections;
using System.Web;
using System.Web.Security;
using System.Web.UI;
using System.Web.UI.WebControls;
using System.Web.UI.WebControls.WebParts;
using System.Web.UI.HtmlControls;
using System.Text;
public partial class AsyncDropDownListExample_AsyncDropDownListExample :
System.Web.UI.Page, ICallbackEventHandler
{
private DataSet lookupData = null;
protected void Page_Load(object sender, EventArgs e)
{
// Get our callback event reference
string js = Page.ClientScript.GetCallbackEventReference(this,“arg”,“OnServerCallComplete”, “ctx”, “OnServerCallError”, true);
// Create a simplified wrapper method
StringBuilder newFunction = new StringBuilder();
newFunction.Append(“function StartAsyncCall(arg, ctx) “);
newFunction.Append(“{ “);
newFunction.Append(js);
newFunction.Append(“ } “);
// Now register it
Page.ClientScript.RegisterClientScriptBlock(this.GetType(),
“NewAsyncMethod”,
newFunction.ToString(), true);
}
#region ICallbackEventHandler Members
public string GetCallbackResult()
{
StringBuilder ids = new StringBuilder();
StringBuilder names = new StringBuilder();
int rowCnt = 0;
int numRows = lookupData.Tables[0].Rows.Count;
foreach (DataRow row in lookupData.Tables[0].Rows)
{
rowCnt++;
ids.Append(row[“ID”].ToString());
if (rowCnt < numRows) // Only append a separator if its NOT the last
element
ids.Append(“|”); // Include a data element separator character
names.Append(row[“Name”].ToString());
if (rowCnt < numRows) // Only append a separator if its NOT the last element
names.Append(“|”); // Include a data element separator character
}
// Make one big string, separating the sets of data with a tilde ‘~’
string returnData = string.Format(“{0}~{1}”, ids.ToString(),
names.ToString());
return returnData;
}
public void RaiseCallbackEvent(string eventArgument)
{
System.Threading.Thread.Sleep(2000); // Simulate a delay
lookupData = GetLookupValuesFromDatabase();
}
#endregion
#region GetLookupValuesFromDatabase helper method
private DataSet GetLookupValuesFromDatabase()
{
DataSet ds = new DataSet();
DataTable dt = new DataTable();
DataColumn idCol = new DataColumn(“ID”, typeof(int));
DataColumn nameCol = new DataColumn(“Name”, typeof(string));
dt.Columns.Add(idCol);
dt.Columns.Add(nameCol);
dt.AcceptChanges();
DataRow newRow = null;
newRow = dt.NewRow();
newRow[idCol] = 1;
newRow[nameCol] = “Joe Bloggs ID#1”;
dt.Rows.Add(newRow);
newRow = dt.NewRow();
newRow[idCol] = 2;
newRow[nameCol] = “Mr A. Nonymous ID#2”;
dt.Rows.Add(newRow);
newRow = dt.NewRow();
newRow[idCol] = 3;
newRow[nameCol] = “Mrs N. Extdoorneighbour ID#3”;
dt.Rows.Add(newRow);
newRow = dt.NewRow();
newRow[idCol] = 4;
newRow[nameCol] = “Mr. Pea Body ID#4”;
dt.Rows.Add(newRow);
ds.Tables.Add(dt);
ds.AcceptChanges();
return ds;
}
#endregion
}
Web Page:
Código:
<%@ Page Language=”C#” AutoEventWireup=”true”
CodeFile=”AsyncDropDownListExample.aspx.cs”
Inherits=”AsyncDropDownListExample_AsyncDropDownListExample” %>
<!DOCTYPE html PUBLIC “-//W3C//DTD XHTML 1.0 Transitional//EN”
“http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd”>
<html xmlns=”http://www.w3.org/1999/xhtml” >
<head runat=”server”>
<title>Asynchronous Drop Down List Example</title>
<script type=”text/javascript”>
function LoadListItems()
{
StartAsyncCall(null,null);
}
function OnServerCallComplete(arg, ctx)
{
var idsAndNames = arg.split(“~”);
var ids = idsAndNames[0].split(“|”);
var names = idsAndNames[1].split(“|”);
var htmlCode;
var ddl = document.getElementById(“ddlList”);
for (var i=0; i < ids.length; i++)
{
htmlCode = document.createElement(‘option’);
// Add the new <OPTION> node to our <SELECT> drop list
ddl.options.add(htmlCode);
// Set the <OPTION> display text and value;
htmlCode.text = names[i];
htmlCode.value = ids[i];
}
// Enable our drop down list as it
// should have some values now.
ddl.disabled = false;
}
function OnServerCallError(err, ctx)
{
alert(“There was an error processing the request! Error was [“ + err +
“]”);
}
function OnDropListSelectChanged()
{
var ddl = document.getElementById(“ddlList”);
// Display selected value
var msg = document.getElementById(“msg”);
msg.firstChild.nodeValue=ddl.value;
}
</script>
</head>
<body onload=”LoadListItems();”>
<form id=”form1” runat=”server”>
<div>
<select id=”ddlList” disabled=”false”
onchange=”OnDropListSelectChanged();”>
<option>(Loading values from the Server)</option>
</select>
</div>
<hr />
<div>
<label>Value Selected: </label><span id=”msg”>{none}</span>
</div>
</form>
</body>
</html>
Espero que le pueda ser útil a alguien más...Saludos!! ;) |