在WebForm中跳过SqlDataSource中sql参数的设置值

Question

我正在asp.net中创建一个WebForm,我想用asp中的数据显示gridview:SqlDataSource
当我尝试跳过(传递null)某些参数的值时,我的问题变成了.

这是我的代码的一些片段

在aspx文件中sqldatasource看起来像

<asp:SqlDataSource ID="SqlDataSource1" runat="server" 
        ConnectionString="<%$ ConnectionStrings:ApplicationServices %>" 
        SelectCommand="art_bat_art" SelectCommandType="StoredProcedure">
        <SelectParameters>
            <asp:Parameter Name="art_naz" DefaultValue="HLA"  ConvertEmptyStringToNull="true" Type="String" />
            <asp:Parameter Name="art_sifra"     DbType="String"  Direction="Input"/>
            <asp:Parameter Name="vrsta_id" DefaultValue="3"   ConvertEmptyStringToNull="true" Type="Int32" />     
            <asp:Parameter Name="podvrsta_id" DefaultValue="13"   ConvertEmptyStringToNull="true" 
                Type="Int32"  />
            <asp:Parameter Name="podgrupa2"  DefaultValue="1365"   ConvertEmptyStringToNull="true" Type="Int32"      /> 
            <asp:Parameter Name="podosobine"   DefaultValue="1:9241"  ConvertEmptyStringToNull="true" 
                Type="String"  />
            <asp:Parameter Name="podosobineOR" DefaultValue="true"   ConvertEmptyStringToNull="true" 
                Type="Boolean"  />
        </SelectParameters>

我的网格看起来像这样:

 <asp:GridView ID="GridView1" runat="server" AutoGenerateColumns="False" 
        DataKeyNames="id" DataSourceID="SqlDataSource1">

代码后面出现问题我的存储过程的一个参数是可选的,如果我在SQL中将它作为null传递,那么无论如何都会执行存储过程.

我试图跳过并传递该参数如下

public partial class _Default : System.Web.UI.Page
    {
        protected void Page_Load(object sender, EventArgs e)
        {


        }
        protected void Button1_Click1(object sender, EventArgs e)
        {
            SqlDataSource1.SelectParameters["art_sifra"].DefaultValue = DBNull.Value; //Cannot implicitly convert type 
            SqlDataSource1.SelectParameters["art_sifra"].DefaultValue = System.Data.SqlTypes.SqlString.Null;   //Cannot implicitly convert type 
            SqlDataSource1.SelectParameters["art_sifra"].DefaultValue = System.Data.SqlTypes.SqlString.Null.ToString();   //IT compiles but i get NULL as text in SQL
            //IF I Just skip seting of this parametar, My SqlDataSource won't call stored proce 
            SqlDataSource1.SelectParameters["art_sifra"].DefaultValue = string.Empty; //Again no execution of stored proce
            //Even if I call SqlDataSource1.DataBind(); //nothing cames to sql 
            GridView1.DataBind();
        }
    }

Answer 1

您必须编辑SQL(或存储过程)才能处理可选参数.

即:如果你有:
SELECT blah FROM yourTable WHERE art_sifra = @art_sifra

将其更改为:
SELECT blah FROM yourTable WHERE (art_sifra = @art_sifra OR @art_sifra = '')

然后只需更改ConvertEmptyStringToNull="false"并将select参数设置为"": SqlDataSource1.SelectParameters["art_sifra"].DefaultValue = "";

还需要设置CancelSelectOnNullParameter="false"数据源.