给你一个稍微复杂一点的查询，我设计的
看上图我把第一列标签后面的控件命名有规律，比如计划工厂后面文本框是"计划工厂t"，Exapt命名为"计划工厂c"，后面还隐藏一个listbox，命名为"计划工厂l"。
计划工厂 这个名称本身就是我要查询的表里面包含的字段。
利用这种界面，我要完成一些复杂点的查询：点文本框里的小图标按钮，d出工具，可以输入多条件，条件可以成立为模糊条件（用*代替不认识部分），也可以成立为否决条件。
选中Exapt全部否定所成立条件；点击执行按钮，有条件的成立条件，无条件的不成立。
所以这种东西贯穿软件我就不能每个都去做，就只能写一个类文件：
public class conditionset{
public void load_condit(Panel p)
{
foreach (Control ctl in p.Controls)
{
if (ctl is SkinTextBox)
{
SkinTextBox sktxt = (SkinTextBox)p.Controls[ctl.Name]
ListBox list = (ListBox)p.Controls[sktxt.Name.Substring(0, sktxt.Name.Length - 1) + "l"]
sktxt.IconClick += (Object sen, EventArgs ed) =>
{
ctl.condition toolform = new ctl.condition()
if (list.Items.Count > 0)
{
sktxt.Text = "┅"
sktxt.ReadOnly = true
}
foreach (var sm in list.Items)
{
toolform.dv.Rows.Add(sm.ToString())
}
toolform.Show()
toolform.cleari += (Object send, EventArgs er) =>
{
sktxt.Text = ""
sktxt.ReadOnly = false
}
toolform.subm += (Object send, EventArgs er) =>
{
list.Items.Clear()
foreach (DataGridViewRow dvr in toolform.dv.Rows)
{
if (Convert.ToString(dvr.Cells[0].Value) != "")
{
list.Items.Add(Convert.ToString(dvr.Cells[0].Value))
}
}
sktxt.Text = "┅"
sktxt.ReadOnly = true
}
}
}
}
}
public string condit(Panel p)
{
string master_condition = ""
foreach (Control ctl in p.Controls)
{
//遍历panel查找条件
#region
string condition = ""
if (ctl is SkinTextBox)
{
//文本框条件组合
#region
SkinTextBox sktxt = (SkinTextBox)p.Controls[ctl.Name]
string ziduan_name = sktxt.Name.Substring(0, sktxt.Name.Length - 1)
SkinCheckBox skck = (SkinCheckBox)p.Controls[ctl.Name.Substring(0, ctl.Name.Length - 1) + "c"]
ListBox list = (ListBox)p.Controls[ctl.Name.Substring(0, ctl.Name.Length - 1) + "l"]
if (sktxt.Text != "")
{
if (sktxt.Text == "┅")
{
string blur_str = "", blur = ""
foreach (var itm in list.Items)
{
if (itm.ToString().Contains("*"))
{
if (skck.Checked == true)
{
blur += " and " + ziduan_name + " not like '" + itm.ToString().Replace("*", "%") + "'"
}
else
{
blur += " or " + ziduan_name + " like '" + itm.ToString().Replace("*", "%") + "'"
}
}
else
{
blur_str += "'" + Convert.ToString(itm) + "',"
}
}
string blur_sql = (blur == "") ? "" : blur.Substring(4, blur.Length - 4).Trim()
string in_condition = "", like_condition = ""
if (skck.Checked == true)
{
in_condition = ziduan_name + " not in "
like_condition = " and "
}
else
{
in_condition = ziduan_name + " in "
like_condition = " or "
}
string contains_sql = (blur_str == "") ? "" : in_condition + "(" + blur_str.Substring(0, blur_str.Length - 1) + ")"
condition = contains_sql + blur_sql
if (blur_sql != "" && contains_sql != "")
{
condition = contains_sql + like_condition + blur_sql
}
else
{
condition = contains_sql + blur_sql
}
}
else
{
if (!sktxt.Text.Contains("*"))
{
if (skck.Checked == true)
{
condition = ziduan_name + "<>'" + sktxt.Text + "'"
}
else
{
condition = ziduan_name + "='" + sktxt.Text + "'"
}
}
else
{
if (skck.Checked == true)
{
condition = ziduan_name + " not like '" + sktxt.Text.Replace("*", "%") + "'"
}
else
{
condition = ziduan_name + " like '" + sktxt.Text.Replace("*", "%") + "'"
}
}
}
}
#endregion
}
if (ctl is SkinDateTimePicker)
{
//日期条件组合
#region
if (ctl.Name.Substring(ctl.Name.Length - 1, 1) != "t")
{
SkinDateTimePicker skdate_sta = (SkinDateTimePicker)p.Controls[ctl.Name]
SkinDateTimePicker skdate_end = (SkinDateTimePicker)p.Controls[ctl.Name + "t"]
if (skdate_sta.text != "")
{
if (skdate_end.text == "")
{
condition = skdate_sta.Name + "='" + skdate_sta.text + "'"
}
else
{
condition = skdate_sta.Name + ">='" + skdate_sta.text + "' and " + skdate_sta.Name + "<='" + skdate_end.text + "'"
}
}
}
#endregion
}
master_condition += (condition == "") ? "" : "(" + condition + ") and "
#endregion //遍历panel查找条件
}
string condition_sql = (master_condition == "") ? "" : master_condition.Substring(0, master_condition.Length - 5)
return condition_sql
}
}
工具用一个窗体代替：
public partial class condition : Form{
public condition()
{
InitializeComponent()
}
public event EventHandler subm
public event EventHandler cleari
private void submit_Click(object sender, EventArgs e)
{
subm(sender, e)
this.Dispose()
}
private void clearit_Click(object sender, EventArgs e)
{
this.Dispose()
dv.Rows.Clear()
cleari(sender, e)
}
}
当我们执行多条件的时候就等于拼接条件
需要根据查询条件组装sql查询语句。如：string sql="select * from table where 1=1 "
if (条件1)
sql+=" and ....."
if (条件2)
sql+=" and ....."
sql+=" order by ....."
在组装sql语句时注意做类型判断而且要对传进来的条件做防sql注入处理，如过滤' -- drop truncate 等字符及关键字。
在组装好sql语句之后就可以利用ADO.net做查询处理。
看你的代码存在两点疑问，第一，SQL语句构造完成你执行了没，如利用SqlCommand或SqlDataAdapter执行了没？第二，你的SQL语句应该是存在问题，如find+=" and 书名="+bookname这一句，至少是缺少单引号，正确的应该是find+=" and 书名='"+bookname+"'"其它的也类似欢迎分享，转载请注明来源：内存溢出
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