C#用ComboBox控件实现省与市的联动效果的方法
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2023-12-12 16:55:34
本文实例讲述了c#用combobox控件实现省与市的联动效果的方法。分享给大家供大家参考。具体实现方法如下:
复制代码 代码如下:using system; ...
本文实例讲述了c#用combobox控件实现省与市的联动效果的方法。分享给大家供大家参考。具体实现方法如下:
复制代码 代码如下:
using system;
using system.collections.generic;
using system.componentmodel;
using system.data;
using system.drawing;
using system.linq;
using system.text;
using system.windows.forms;
using system.data.sqlclient;
using system.configuration;
namespace 省市联动
{
public partial class form1 : form
{
public form1()
{
initializecomponent();
}
private void form1_load(object sender, eventargs e)
{
tsql.getconnection();
using (sqlconnection conn = new sqlconnection(tsql.getconnection()))
{
conn.open();
using (sqlcommand cmd = conn.createcommand())
{
cmd.commandtext = "select * from promary";
using (sqldatareader dr = cmd.executereader())
{
while (dr.read())
{
province pr = new province();
pr.proid = dr.getint32(dr.getordinal("proid")); //这里要特别注意数据库字段的类型 proid在数据库里是int型
pr.proname = dr.getstring(dr.getordinal("proname"));
combobox1.items.add(pr);//pr是一个province对象。province有一个proname和proid属性。我将一个对象填充到combobox1里。再让combobox1的displaymember属性设置proname。【也就是让combobox1显示pr对象的proname属性】。这样在填充市级城市的时候我就可以找到当前选择项combobox1.selecteditem(或者当前选择对象)所对应的proid
}
}
}
combobox1.selectedindex = 0; //将comcombobox1的默认选项设为0
}
}
private void combobox2_selectedindexchanged(object sender, eventargs e)
{
}
private void combobox1_selectedindexchanged(object sender, eventargs e)
{
combobox2.items.clear(); //在选择的时候先清空一下combox1里面的所以项,以免在更换省名的时候,与先前对应的省名下的市没有删除。
province tem = (province)combobox1.selecteditem; // 因为在combobox1.items.add(pr)里添加的是对象。所以在这里讲combox1所选中的当前对象赋给tem对象 (tem对象下面有两个属性 proname和proid)
int id = tem.proid; //将当前选中对象的的proid赋值给id,给下面的sql查询语句使用
tsql.getconnection();// 获取数据库连接字符串。
using (sqlconnection conn = new sqlconnection(tsql.getconnection()))
{
conn.open();
using (sqlcommand cmd = conn.createcommand())
{
cmd.commandtext = "select * from city where proid=@id";
cmd.parameters.add(new sqlparameter("id", id));
using (sqldatareader dr = cmd.executereader())
{
while (dr.read())
{
combobox2.items.add(dr.getstring(dr.getordinal("cityname")));
}
}
}
combobox2.selectedindex = 0; //将comcombobox1的默认选项设为0
}
}
}
class tsql
{
public static string getconnection() //数据库连接字符串
{
string getconn = configurationmanager.connectionstrings["getconn"].connectionstring;
return getconn;
}
}
class province
{
public string proname { get; set; }
public int proid { get; set; }
}
}
using system.collections.generic;
using system.componentmodel;
using system.data;
using system.drawing;
using system.linq;
using system.text;
using system.windows.forms;
using system.data.sqlclient;
using system.configuration;
namespace 省市联动
{
public partial class form1 : form
{
public form1()
{
initializecomponent();
}
private void form1_load(object sender, eventargs e)
{
tsql.getconnection();
using (sqlconnection conn = new sqlconnection(tsql.getconnection()))
{
conn.open();
using (sqlcommand cmd = conn.createcommand())
{
cmd.commandtext = "select * from promary";
using (sqldatareader dr = cmd.executereader())
{
while (dr.read())
{
province pr = new province();
pr.proid = dr.getint32(dr.getordinal("proid")); //这里要特别注意数据库字段的类型 proid在数据库里是int型
pr.proname = dr.getstring(dr.getordinal("proname"));
combobox1.items.add(pr);//pr是一个province对象。province有一个proname和proid属性。我将一个对象填充到combobox1里。再让combobox1的displaymember属性设置proname。【也就是让combobox1显示pr对象的proname属性】。这样在填充市级城市的时候我就可以找到当前选择项combobox1.selecteditem(或者当前选择对象)所对应的proid
}
}
}
combobox1.selectedindex = 0; //将comcombobox1的默认选项设为0
}
}
private void combobox2_selectedindexchanged(object sender, eventargs e)
{
}
private void combobox1_selectedindexchanged(object sender, eventargs e)
{
combobox2.items.clear(); //在选择的时候先清空一下combox1里面的所以项,以免在更换省名的时候,与先前对应的省名下的市没有删除。
province tem = (province)combobox1.selecteditem; // 因为在combobox1.items.add(pr)里添加的是对象。所以在这里讲combox1所选中的当前对象赋给tem对象 (tem对象下面有两个属性 proname和proid)
int id = tem.proid; //将当前选中对象的的proid赋值给id,给下面的sql查询语句使用
tsql.getconnection();// 获取数据库连接字符串。
using (sqlconnection conn = new sqlconnection(tsql.getconnection()))
{
conn.open();
using (sqlcommand cmd = conn.createcommand())
{
cmd.commandtext = "select * from city where proid=@id";
cmd.parameters.add(new sqlparameter("id", id));
using (sqldatareader dr = cmd.executereader())
{
while (dr.read())
{
combobox2.items.add(dr.getstring(dr.getordinal("cityname")));
}
}
}
combobox2.selectedindex = 0; //将comcombobox1的默认选项设为0
}
}
}
class tsql
{
public static string getconnection() //数据库连接字符串
{
string getconn = configurationmanager.connectionstrings["getconn"].connectionstring;
return getconn;
}
}
class province
{
public string proname { get; set; }
public int proid { get; set; }
}
}
复制代码 代码如下:
using system.data.sqlclient;
namespace 省市选择2
{
public partial class form1 : form
{
publicform1()
{
initializecomponent();
}
privatevoid form1_load(objectsender,eventargs e)
{
/*
//测试代码:执行这段代码的情况下是可以吧 tom这个值添加到 combobox1中的。
people p1 = new people();
p1.name = "tom";
p1.age = 25;
combobox1.items.add(p1.name);
*/
using(sqlconnection conn =newsqlconnection("data source=凡斌-vaio;initialcatalog=dbpromary;integrated security=true"))
{
conn.open();
using(sqlcommand cmd = conn.createcommand())
{
cmd.commandtext = "select * from promary";
using(sqldatareader reader = cmd.executereader())
{
while (reader.read())
{
//string str =reader.getstring(reader.getordinal("proname"));
//combobox1.items.add(str);
province pv =new province();
//将combobox1控件的displaymember属性设置为“provincename”用来在combobox1控件中显示provincename属性的值
combobox1.displaymember = "provincename";
pv.provincename =reader.getstring(reader.getordinal("proname"));
pv.provinceid =reader.getint32(reader.getordinal("proid"));
//虽然pv属于对象,把一个对象添加到comboxbox1中,控件显示的值为对象的类名,但是在前面combobox1.displaymember ="provincename"处已经设置好控件要显示的为 province类的provincename值,所以添加进去的是pv对象的provincename值
combobox1.items.add(pv);
}
}
}
}
}
privatevoid combobox1_selectedindexchanged(object sender,eventargse) //注意这里是combobox1不是combobox2
{
try
{
province tem = (province) combobox1.selecteditem;
int id = tem.provinceid;
combobox2.items.clear();
using(sqlconnection conn =newsqlconnection("data source=凡斌-vaio;initialcatalog=dbpromary;integrated security=true"))
{
conn.open();
using (sqlcommand cmd = conn.createcommand())
{
//查询city(市)表里的 proid与promary(省)表里proid相同的所有数据。
cmd.commandtext = "select * from city where proid =@id";
cmd.parameters.add(new sqlparameter("id", id));
sqldatareader dr = cmd.executereader();
while(dr.read())
{
combobox2.items.add(dr.getstring(dr.getordinal("cityname")));
}
}
}
}
catch(exception ex)
{
messagebox.show("错误信息:" + ex.message);
}
}
}
class province
{
public string provincename { get;set; }
public int provinceid { get;set; }
}
//class people
//{
// public string name { get; set; }
// public int age { get; set; }
//}
}
namespace 省市选择2
{
public partial class form1 : form
{
publicform1()
{
initializecomponent();
}
privatevoid form1_load(objectsender,eventargs e)
{
/*
//测试代码:执行这段代码的情况下是可以吧 tom这个值添加到 combobox1中的。
people p1 = new people();
p1.name = "tom";
p1.age = 25;
combobox1.items.add(p1.name);
*/
using(sqlconnection conn =newsqlconnection("data source=凡斌-vaio;initialcatalog=dbpromary;integrated security=true"))
{
conn.open();
using(sqlcommand cmd = conn.createcommand())
{
cmd.commandtext = "select * from promary";
using(sqldatareader reader = cmd.executereader())
{
while (reader.read())
{
//string str =reader.getstring(reader.getordinal("proname"));
//combobox1.items.add(str);
province pv =new province();
//将combobox1控件的displaymember属性设置为“provincename”用来在combobox1控件中显示provincename属性的值
combobox1.displaymember = "provincename";
pv.provincename =reader.getstring(reader.getordinal("proname"));
pv.provinceid =reader.getint32(reader.getordinal("proid"));
//虽然pv属于对象,把一个对象添加到comboxbox1中,控件显示的值为对象的类名,但是在前面combobox1.displaymember ="provincename"处已经设置好控件要显示的为 province类的provincename值,所以添加进去的是pv对象的provincename值
combobox1.items.add(pv);
}
}
}
}
}
privatevoid combobox1_selectedindexchanged(object sender,eventargse) //注意这里是combobox1不是combobox2
{
try
{
province tem = (province) combobox1.selecteditem;
int id = tem.provinceid;
combobox2.items.clear();
using(sqlconnection conn =newsqlconnection("data source=凡斌-vaio;initialcatalog=dbpromary;integrated security=true"))
{
conn.open();
using (sqlcommand cmd = conn.createcommand())
{
//查询city(市)表里的 proid与promary(省)表里proid相同的所有数据。
cmd.commandtext = "select * from city where proid =@id";
cmd.parameters.add(new sqlparameter("id", id));
sqldatareader dr = cmd.executereader();
while(dr.read())
{
combobox2.items.add(dr.getstring(dr.getordinal("cityname")));
}
}
}
}
catch(exception ex)
{
messagebox.show("错误信息:" + ex.message);
}
}
}
class province
{
public string provincename { get;set; }
public int provinceid { get;set; }
}
//class people
//{
// public string name { get; set; }
// public int age { get; set; }
//}
}
如下图所示:
希望本文所述对大家的c#程序设计有所帮助。