protected void Button2_Click(object sender, EventArgs e)
{
SqlConnection cn = database.creatdatabase();
cn.Open();
if (CheckBox2.Checked == true)
{
string aa = "select 商品编号,商品名,型号,品牌,剩余数量,出售量 from Product";
SqlCommand cmd = new SqlCommand(aa, cn);
DataSet ds = new DataSet();
string oo = cmd.ExecuteScalar().ToString();
SqlDataAdapter sda = new SqlDataAdapter(cmd);
sda.Fill(ds, "product");
GridView2.DataSource = ds.Tables["product"].DefaultView;
GridView2.DataBind();
}
else if (TextBox2.Text.ToString().Trim() == "")
{
Response.Write("<script>alert('请输入值');</script>");
}
else
{
string ii = "select 商品编号,商品名,型号,品牌,剩余数量,出售量 from Product where '" + DropDownList2.SelectedItem .Value .Trim () + "'='" + TextBox2.Text.ToString().Trim() + "'";
SqlCommand cmd1 = new SqlCommand(ii, cn);
DataSet dd = new DataSet();
string kk = cmd1.ExecuteScalar().ToString();
SqlDataAdapter sd = new SqlDataAdapter(cmd1);
sd.Fill(dd, "all");
GridView2.DataSource = dd.Tables["all"].DefaultView;
GridView2.DataBind();
}
}
运行了出现这个错误: 异常详细信息: System.NullReferenceException: 未将对象引用设置到对象的实例。 源错误:
行 42: SqlCommand cmd1 = new SqlCommand(ii, cn);
行 43: DataSet dd = new DataSet();
行 44: string kk = cmd1.ExecuteScalar().ToString();
行 45: SqlDataAdapter sd = new SqlDataAdapter(cmd1);
行 46: sd.Fill(dd, "all");
请高手看一下什么原因
{
SqlConnection cn = database.creatdatabase();
cn.Open();
if (CheckBox2.Checked == true)
{
string aa = "select 商品编号,商品名,型号,品牌,剩余数量,出售量 from Product";
SqlCommand cmd = new SqlCommand(aa, cn);
DataSet ds = new DataSet();
string oo = cmd.ExecuteScalar().ToString();
SqlDataAdapter sda = new SqlDataAdapter(cmd);
sda.Fill(ds, "product");
GridView2.DataSource = ds.Tables["product"].DefaultView;
GridView2.DataBind();
}
else if (TextBox2.Text.ToString().Trim() == "")
{
Response.Write("<script>alert('请输入值');</script>");
}
else
{
string ii = "select 商品编号,商品名,型号,品牌,剩余数量,出售量 from Product where '" + DropDownList2.SelectedItem .Value .Trim () + "'='" + TextBox2.Text.ToString().Trim() + "'";
SqlCommand cmd1 = new SqlCommand(ii, cn);
DataSet dd = new DataSet();
string kk = cmd1.ExecuteScalar().ToString();
SqlDataAdapter sd = new SqlDataAdapter(cmd1);
sd.Fill(dd, "all");
GridView2.DataSource = dd.Tables["all"].DefaultView;
GridView2.DataBind();
}
}
运行了出现这个错误: 异常详细信息: System.NullReferenceException: 未将对象引用设置到对象的实例。 源错误:
行 42: SqlCommand cmd1 = new SqlCommand(ii, cn);
行 43: DataSet dd = new DataSet();
行 44: string kk = cmd1.ExecuteScalar().ToString();
行 45: SqlDataAdapter sd = new SqlDataAdapter(cmd1);
行 46: sd.Fill(dd, "all");
请高手看一下什么原因
这错了把.
string aa ="select id as 商品编号..... from Product":
45行改成 SqlDataAdapter sd = new SqlDataAdapter(ii,cn)试一下
private static DataSet SelectRows(DataSet dataset,
string connectionString,string queryString)
{
using (SqlConnection connection =
new SqlConnection(connectionString))
{
SqlDataAdapter adapter = new SqlDataAdapter();
adapter.SelectCommand = new SqlCommand(
queryString, connection);
adapter.Fill(dataset);
return dataset;
}
}