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POSTing Data with ASP.NET
By Steven Smith
Thanks to Alex Lowe for this updated code. Using the
example code listed below, you can easily convert the page scraping code described in the last article to
use the POST protocol. This will allow you to submit form information to sites and retrieve the results,
which allows for great interop opportunities. We covered the basics of this technique in the
last article,
so now I'm just going to demonstrate the code.
/stevesmith/articles/examples/cs/postscrape.aspx<%@ Import Namespace="System.Net" %>
<%@ Import Namespace="System.IO" %>
<script language="C#" runat="server">
void Page_Load(Object Src, EventArgs E) {
myPage.Text = readHtmlPage("http://aspalliance.com/aldotnet/examples/posttest.asp");
}
private String readHtmlPage(string url)
{
String result = "";
String strPost = "x=1&y=2&z=YouPostedOk";
StreamWriter myWriter = null;
HttpWebRequest objRequest = (HttpWebRequest)WebRequest.Create(url);
objRequest.Method = "POST";
objRequest.ContentLength = strPost.Length;
objRequest.ContentType = "application/x-www-form-urlencoded";
try
{
myWriter = new StreamWriter(objRequest.GetRequestStream());
myWriter.Write(strPost);
}
catch (Exception e)
{
return e.Message;
}
finally {
myWriter.Close();
}
HttpWebResponse objResponse = (HttpWebResponse)objRequest.GetResponse();
using (StreamReader sr =
new StreamReader(objResponse.GetResponseStream()) )
{
result = sr.ReadToEnd();
// Close and clean up the StreamReader
sr.Close();
}
return result;
}
</script>
<html>
<body>
<b>This content is being populated from a separate HTTP request to
<a href="http://aspalliance.com/aldotnet/examples/posttest.asp">
http://aspalliance.com/aldotnet/examples/posttest.asp</a>:</b><hr/>
<asp:literal id="myPage" runat="server"/>
</body>
</html>
/stevesmith/articles/examples/vb/postscrape.aspx<%@ Import Namespace="System.Net" %>
<%@ Import Namespace="System.IO" %>
<script language="vb" runat="server">
Sub Page_Load(ByVal Src As Object, ByVal E As EventArgs)
myPage.Text = readHtmlPage("http://aspalliance.com/aldotnet/examples/posttest.asp")
End Sub
Function readHtmlPage(ByVal url As String) As String
Dim result As String = ""
Dim strPost As String = "x=1&y=2&z=YouPostedOk"
Dim myWriter As StreamWriter
Dim objRequest As HttpWebRequest = WebRequest.Create(url)
objRequest.Method = "POST"
objRequest.ContentLength = strPost.Length
objRequest.ContentType = "application/x-www-form-urlencoded"
Try
myWriter = new StreamWriter(objRequest.GetRequestStream())
myWriter.Write(strPost)
Catch e As Exception
return e.Message
Finally
myWriter.Close()
End Try
Dim objResponse As HttpWebResponse = objRequest.GetResponse()
Dim sr As StreamReader
sr = New StreamReader(objResponse.GetResponseSTream())
result = sr.ReadToEnd()
sr.Close()
Return result
End Function
</script>
<html>
<body>
<b>This content is being populated from a separate HTTP request to
<a href="http://aspalliance.com/aldotnet/examples/posttest.asp">
http://aspalliance.com/aldotnet/examples/posttest.asp</a>:</b><hr/>
<asp:literal id="myPage" runat="server"/>
</body>
</html>
//coming soon
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| C# |
VB |
JScript |
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