Boolean IsFirst=True;
foreach (ListItem item in ListBox1.Items)
{
 
    if (item.Selected)
    {
            if (IsFirst)
              {
                com2.Parameters["@ListBox1"].Value = item.Text;
                IsFirst=False;
              }
            else
              {
                com2.Parameters["@ListBox1"].Value +=","+ item.Text;
              }
     }
}

希望这是您的完美解决方案

Hopefully It is your perfect solution

string strSelected = string.Empty;
foreach (ListItem item in ListBox1.Items)
{
    if (item.Selected)
    {
           if(strselected == string.empty)
              strselected = item.text
           else
              strSelected += "," + item.Text 
    }
   
}

请使用以下代码来修饰逗号:

Hi,

Please use following code for trimming comma:

string strSelected = string.Empty;
foreach (ListItem item in ListBox1.Items)
{ 
    if (item.Selected)
    { 
        strSelected += item.Text + ",";
    }
    strSelected = strSelected.TrimEnd(',');
    
}
com2.Parameters["@ListBox1"].Value = strSelected;