两个小问题，请求帮助？

goodluck20131313 2011-07-05 10:31:50

在WINFROM 中，问题一，提示：未将对象引用设置到对象的实例
private void Bindstate()
{
List<ListItem> items = new List<ListItem>();
items.Add(new ListItem("0", "所有状态"));
items.Add(new ListItem("1", "审核"));
items.Add(new ListItem("2", "结算"));
ddlstate.DisplayMember = "Text"; //显示
ddlstate.ValueMember = "Value"; //值
ddlstate.DataSource = items;
}
private void listFrm_Load(object sender, EventArgs e)
{
Bindstate();
BindData();

}
private void BindData()
{
string dd = ddlstate.SelectedValue.ToString();//提示：未将对象引用设置到对象的实例
}
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问题2：
以下主要用于组合查询
DataTable dt = new DataTable();
if (ddlnetwork.SelectedValue.ToString() != "0")
{
string network=ddlnetwork.SelectedValue.ToString();
sql2 = sql2 + "and a.chitty_network='"+network+"'";
}
if (txtkey.Text != "")
{
string key = txtkey.Text.Trim();
sql2 = sql2 + "and ((select corp_name from p_corp where corp_id=a.chitty_corp) like '%"+key+"%' or (select corp_name from p_corp where corp_id=a.chitty_corp2) like '%"+key+"%')";
}

string sql = "select a.* from p_sale a where 1=1" + sql2;
MessageBox.Show(sql);
为什么输出的是相当长的一字符串：select a.* from p_sale a where 1=1and ((select corp_name from p_corp where corp_id=a.sale_corp) like '%select a.* from p_sale a where 1=1and ((select corp_name from p_corp where corp_id=a.sale_corp) like '%select a.* from p_sale a where 1=1and ((select corp_name from p_corp where corp_id=a.sale_corp) like '%select a.* from p_sale a where 1=1and a.sale_network='1'and ((select corp_name from p_corp where corp_id=a.sale_corp) like '%select a.* from p_sale a where 1=1and a.sale_network='System.Data.DataRowView'and ((select corp_name from p_corp where corp_id=a.sale_corp) like '%select a.* from p_sale a where 1=1and a.sale_network='System.Data.DataRowView'and ((select corp_name from p_corp where corp_id=a.sale_corp) like '%输入单号/发货方/收货方/装车号/备注查询%' or (select corp_name from p_corp where corp_id=a.sale_corp2) like '%输入单号/发货方/收货方/装车号/备注查询%')%' or (select corp_name from p_corp where corp_id=a.sale_corp2) like '%select a.* from p_sale a where 1=1and a.sale_network='System.Data.DataRowView'and ((select corp_name from p_corp where corp_id=a.sale_corp) like '%输入单号/发货方/收货方/装车号/备注查询%' or (select corp_name from p_corp where corp_id=a.sale_corp2) like '%输入单号/发货方/收货方/装车号/备注查询%')%')%' or (select corp_name from p_corp where corp_id=a.sale_corp2) like '%select a.* from p_sale a where 1=1and a.sale_network='System.Data.DataRowView'and ((select corp_name from p_corp where corp_id=a.sale_corp) like '%select a.* from p_sale a where 1=1and a.sale_network='System.Data.DataRowView'and ((select corp_name from p_corp where corp_id=a.sale_corp) like '%输入单号/发货方/收货方/装车号/备注查询%' or (select corp_name from p_corp where corp_id=a.sale_corp2) like '%输入单号/发货方/收货方/装车号/备注查询%')%'。。。。。。。。。。。。。。。。。。。。。

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