How to use input controls on SharePoint custom web part?

I am creating my fi开发者_运维百科rst custom web part (visual web part) for SharePoint server 2010.

I added some controls (text boxes) by drag 'n drop and I use them on a form to create new sites.

I thought I could use the usual

    string siteName = txtSiteName.ToString();
    string siteDescription = txtSiteDescription.ToString();

And then (just a small part of the code)

newWeb = SPContext.GetContext(HttpContext.Current).Web.Webs.Add(
siteUrl, siteName, siteDescription, (uint)1033, "STS#1", true, false); 

It works when I create a site for the first time but the second time I get

<nativehr>0x800700b7</nativehr><nativestack></nativestack>
The Web site address "/mySite/System.Web.UI.WebControls.TextBox" is already in use. 

How am I suppose to use web form controls when I create a web part?

Thanks in advance.

I realized I have to use .Text instead of .ToString()

    string siteName = txtSiteName.Text;
    string siteDescription = txtSiteDescription.Text;