gridview的下拉列表问题 [英] dropdownlist problem with gridview

问题描述

如果我从下拉列表中选择模型并在文本框中写入模型，那么它在gridview中显示值但是当我从下拉列表中选择sn时它没有显示任何内容。请帮助我

if i select model from dropdownlist and write model in text box then it show value in gridview but when i select sn from dropdownlist it shows nothing.please help me

SqlConnection con;
con = new SqlConnection(connstring);
con.Open();

//string str = "SELECT * FROM ['ISB VAS Nodes$']";
if (DropDownList1.Text == "Model")
{
    string str = "SELECT * FROM ['ISB VAS Nodes$'] where Model='" + TextBox2.Text + "'";
    //city is the column name in table
    SqlCommand cmd;
    cmd = new SqlCommand(str, con);
    SqlDataReader dr;
    dr = cmd.ExecuteReader();
    if (dr.Read())
    {
        //if city is in 0 index of table
        GridView1.DataSource = dr;
        GridView1.DataBind();
    }
    else
    {
        Response.Write("City does not exist");
    }
    dr.Close();
    con.Close();
}
else if(DropDownList1.Text=="SN") 
{
    string str = "SELECT * FROM ['ISB VAS Nodes$'] where SN='" + TextBox2.Text + "'";
    //city is the column name in table
    SqlCommand cmd;
    cmd = new SqlCommand(str, con);
    SqlDataReader dr;
    dr = cmd.ExecuteReader();
    if (dr.Read())
    {
        //if city is in 0 index of table
        GridView1.DataSource = dr;
        GridView1.DataBind();
    }
    else
    {
        Response.Write("City does not exist");
    }
    dr.Close();
    con.Close();
}

推荐答案

'];
if （DropDownList1.Text == Model）
{
string str = SELECT * FROM [' ISB VAS节点

']"; if (DropDownList1.Text == "Model") { string str = "SELECT * FROM ['ISB VAS Nodes

']其中Model =' + TextBox2.Text + ';
// city是表格中的列名
SqlCommand cmd;
cmd = new SqlCommand（str，con）;
SqlDataReader dr;
dr = cmd.ExecuteReader（）;
if （dr.Read（））
{
// 如果city在表的0索引中
GridView1.DataSou rce = dr;
GridView1.DataBind（）;
}
else
{
Response.Write（ 城市不存在）;
}
dr.Close（）;
con.Close（）;
}
else if （DropDownList1.Text == SN）
{
string str = SELECT * FROM ['ISB VAS Nodes

'] where Model='" + TextBox2.Text + "'"; //city is the column name in table SqlCommand cmd; cmd = new SqlCommand(str, con); SqlDataReader dr; dr = cmd.ExecuteReader(); if (dr.Read()) { //if city is in 0 index of table GridView1.DataSource = dr; GridView1.DataBind(); } else { Response.Write("City does not exist"); } dr.Close(); con.Close(); } else if(DropDownList1.Text=="SN") { string str = "SELECT * FROM ['ISB VAS Nodes

']其中SN =' + TextBox2.Text + ';
// city是表中的列名
SqlCommand cmd;
cmd = new SqlCommand（str，con）;
SqlDataReader dr;
dr = cmd.ExecuteReader（）;
if （dr.Read（））
{
// 如果city在表的0索引中
GridView1.DataSource = dr;
GridView1.DataBind（）;
}
else
{
Response.Write（ 城市不存在）;
}
dr.Close（）;
con.Close（）;
}

'] where SN='" + TextBox2.Text + "'"; //city is the column name in table SqlCommand cmd; cmd = new SqlCommand(str, con); SqlDataReader dr; dr = cmd.ExecuteReader(); if (dr.Read()) { //if city is in 0 index of table GridView1.DataSource = dr; GridView1.DataBind(); } else { Response.Write("City does not exist"); } dr.Close(); con.Close(); }

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