C# foreach遍历的问题

foreach(var i in a)//a里有3个数1,2,3
{
TextBox txt = (TextBox)this.FindControl("txt" + i.ToString());
if (txt !=null)
{
txt.Text = i.ToString();
}
}

给3个text分别指定一个名称。

foreach...
{
TextBox txt = (TextBox)this.FindControl("txt" + a.ToString());
}

foreach(var i in a)
{
TextBox txt = (TextBox)this.FindControl("txt" + i.ToString(),true);

}

for(i=1;i<=3;i++)
{
TextBox txt = (TextBox)this.FindControl("txt" + i.ToString(),true);
}