this.Page.ClientScript.RegisterClientScriptBlock问题
this.Page.ClientScript.RegisterClientScriptBlock(this.GetType(), "alert", "<script type=text/javascript >alert(货品类型名称不能为空！')</script>");
为什么不能弹出窗口呢？

------解决方案--------------------
this.Page.ClientScript.RegisterClientScriptBlock(this.GetType(), "alert", " <script type=text/javascript >alert('货品类型名称不能为空！'); </script>"); 

你少了单引号了.最好加上分号.

------解决方案--------------------
if(!this.Page.ClientScript.IsRegisterClientScriptBlockered("alert"))
{
this.Page.ClientScript.RegisterClientScriptBlock(this.GetType(), "alert", " <script language='javascript' >alert(货品类型名称不能为空！') </script>"); 
}