为什么下拉列表插入“SELECT”将项目列入SQL？ [英] Why the dropdown list insert "SELECT" list item into SQL?

问题描述

我已经在asp.net c＃web表单中编写了以下代码：

i have written the following code in asp.net c# web form:

<asp:DropDownList ID="ddltype" runat="server" CssClass="dropspace" Style="width: 95%; float: left">
                                            <asp:ListItem >SELECT YOUR GADGET</asp:ListItem>
                                            <asp:ListItem >Laptop</asp:ListItem>
                                            <asp:ListItem >Desktop</asp:ListItem>
                                            <asp:ListItem >Printer</asp:ListItem>
                                        </asp:DropDownList>

问题是当我点击提交按钮时没有从下拉列表中选择任何项目，它将SELECT YOUR GADGET插入到sql数据库中。请帮我解决这个问题。请编写c＃代码，以便它不能将第一个列表项值插入数据库。



我尝试过：

the problem is that when i click on submit button without selecting any item from dropdown list it insert "SELECT YOUR GADGET" into the sql database. please help me out from this problem. please write the c# code so that it can not insert first list item value to the data base.

What I have tried:

if(ddltype.selectedValue !="")
{ cmd = new SqlCommand("sp_submitquery", con);
            cmd.CommandType = CommandType.StoredProcedure;
            cmd.Parameters.Add("@gadget", SqlDbType.VarChar).Value = ddltype.SelectedValue;
            

            cmd.ExecuteNonQuery();
          

              ScriptManager.RegisterClientScriptBlock(this, typeof(Page), "anything", "alert('Your Query Submitted Sucessfully');", true);
}



 if (ddltype.SelectedValue == "")
        {
            ScriptManager.RegisterClientScriptBlock(this, typeof(Page), "anything", "alert('Please select your gadget');", true);
        }

推荐答案

我认为这将是您的解决方案..

I think this would be your solution..

if(ddltype.selectedindex==0)
{
ScriptManager.RegisterClientScriptBlock(this, typeof(Page), "anything", "alert('Please select your gadget');", true);
return;
}
if(ddltype.selectedValue !="")
{ cmd = new SqlCommand("sp_submitquery", con);
cmd.CommandType = CommandType.StoredProcedure;
cmd.Parameters.Add("@gadget", SqlDbType.VarChar).Value = ddltype.SelectedValue;


cmd.ExecuteNonQuery();


ScriptManager.RegisterClientScriptBlock(this, typeof(Page), "anything", "alert('Your Query Submitted Sucessfully');", true);
}

> asp：ListItem > 选择你的GADGET < / asp：ListItem >

<asp:ListItem >SELECT YOUR GADGET</asp:ListItem>

put

Value =0

u也可以使用InitialValue =0

put
Value="0"
u can also validate with a requiredfiled validator using InitialValue="0"

如果将index设置为0.那么您将在保存数据之前获得默认索引值，然后将此索引值检查为0，然后根据需要触发弹出窗口。

If you set index as a 0. So you will get the default index value before saving the data and then you check this index value as a 0 or not and fire the popup whatever you want.

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