如何在3Tier架构中编写选择查询？ [英] How to Write Select Query in 3Tier architecture?

问题描述

这是aspx.cs文件的代码



protected void Page_Load（object sender，EventArgs e）

{

if（Request.QueryString [eid]！= null）

{

if（！Page.IsPostBack）

{

SqlDataAdapter da1 = new SqlDataAdapter（select * from tbl_catinfo where cat_id =''+ Request.QueryString [eid] +''，con）;

DataTable dt1 = new DataTable（）;

da1.Fill（dt1）;

txtID.Text = dt1.Rows [0] [0] .ToString（）;

txtCategory.Text = dt1.Rows [0] [1] .ToString（）;

ddlStatus.SelectedValue = dt1.Rows [0] [2] .ToString（ ）;

}

}

}



这是aspx代码

Here is aspx.cs file code

protected void Page_Load(object sender, EventArgs e)
{
if (Request.QueryString["eid"] != null)
{
if (!Page.IsPostBack)
{
SqlDataAdapter da1 = new SqlDataAdapter("Select * from tbl_catinfo where cat_id = ''" + Request.QueryString["eid"] + "''", con);
DataTable dt1 = new DataTable();
da1.Fill(dt1);
txtID.Text = dt1.Rows[0][0].ToString();
txtCategory.Text = dt1.Rows[0][1].ToString();
ddlStatus.SelectedValue = dt1.Rows[0][2].ToString();
}
}
}

Here is aspx code

<asp:GridView ID="GridView1" runat="server" AutoGenerateColumns="False">
<Columns>
<pre lang="xml">&lt;asp:TemplateField HeaderText=&quot;Action&quot;&gt;

                &lt;ItemTemplate&gt;</pre>


 <a href="AddCategory.aspx?eid=<%# Eval("cat_id") %>"><img src="images/icon_edit.gif" alt="Edit" width="16" height="16" border="0"   /></a>
</ItemTemplate>
            </asp:TemplateField>

        </Columns>
    </asp:GridView>

推荐答案

Hello Arpit，



您的案例背后的代码看起来像

Hello Arpit,

The code behind in your case will look something like

protected void Page_Load(object sender, EventArgs e)
{
    if (Request.QueryString["eid"] != null)
    {
        if (!Page.IsPostBack)
        {
            SqlConnection sqlCon;
            SqlCommand sqlCmd;
            SqlDataReader sqlRdr;

             sqlCon = new SqlConnection();   
             sqlCon.ConnectionString = ConfigurationManager.ConnectionStrings["YOURDB"].ConnectionString;   
             sqlCmd = new SqlCommand();
             sqlCmd.CommandText = "SELECT * FROM tbl_catinfo WHERE cat_id = @cat_id";
             sqlCmd.Parameters.Add("@cat_id", Request.QueryString["eid"]);
             sqlCmd.Connection = sqlCon;
             sqlCmd.Connection.Open();
             sqlRdr = sqlCmd.ExecuteReader(CommandBehavior.CloseConnection);
             GridView1.DataSource = sqlRdr;
             GridView1.DataBind();

             sqlCmd.Dispose();
             sqlCon.Dispose();
        }
    }
}

Regards,

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