将值从数据库插入下拉列表失败

本文关键字：下拉列表 失败 插入 数据库 | 更新日期: 2023-09-27 18:16:30

我有州和城市下拉列表(级联)如下:

 protected void BindStateDropDown()
{
    string CS = ConfigurationManager.ConnectionStrings["SportsActiveConnectionString"].ConnectionString;
    using (SqlConnection con = new SqlConnection(CS))
    {
        con.Open();
        SqlCommand cmd = new SqlCommand("select * from tblState", con);
        SqlDataAdapter da = new SqlDataAdapter(cmd);
        DataSet ds = new DataSet();
        da.Fill(ds);
        ddlState.DataSource = ds;
        ddlState.DataTextField = "StateName";
        ddlState.DataValueField = "StateId";
        ddlState.DataBind();
    }
    ddlState.Items.Insert(0, new ListItem("---Select---", "0"));
    ddlCity.Items.Insert(0, new ListItem("---Select---", "0"));
}

protected void ddlState_SelectedIndexChanged(object sender, EventArgs e)
{
    int StatId = Convert.ToInt32(ddlState.SelectedValue);
    string CS = ConfigurationManager.ConnectionStrings["SportsActiveConnectionString"].ConnectionString;
    using (SqlConnection con = new SqlConnection(CS))
    {
        con.Open();
        SqlCommand cmd = new SqlCommand("spCities", con);
        cmd.Parameters.AddWithValue("@StatId", StatId);
        cmd.CommandType = CommandType.StoredProcedure;
        SqlDataAdapter da = new SqlDataAdapter(cmd);
        DataSet ds = new DataSet();
        da.Fill(ds);
        ddlCity.DataSource = ds;
        ddlCity.DataTextField = "CityName";
        ddlCity.DataValueField = "CityId";
        ddlCity.DataBind();
    }
    ddlCity.Items.Insert(0, new ListItem("---Select---", "0"));
}

，我用它向数据库插入值，如下所示:

 cmd.Parameters.AddWithValue("@State", ddlState.SelectedItem.Text);
 cmd.Parameters.AddWithValue("@City", ddlCity.SelectedItem.Text);

这样可以很好地将州和城市插入到数据库表中。现在我试着在编辑页面上显示如下所示的值:

 ddlState.SelectedIndex = ddlState.Items.IndexOf(ddlState.Items.FindByText(rdr["State"].ToString()));
 ddlCity.SelectedIndex = ddlCity.Items.IndexOf(ddlCity.Items.FindByText(rdr["City"].ToString()));

上面的代码绑定了州而不是城市。城市下拉菜单仍然显示——选择——。一旦城市被绑定，我应该能够选择任何其他城市/州，并再次更新它。如有任何帮助，不胜感激

将值从数据库插入下拉列表失败

试试这个

ddlState.SelectedIndex = ddlState.Items.IndexOf(ddlState.Items.FindByText(rdr["State"].ToString()));

则设置城市值为隐藏值hf_city

hf_city.Value = rdr["City"].ToString();

然后关闭阅读器和连接然后再次调用在ddlState_SelectedIndexChanged上创建的函数

 int StatId = Convert.ToInt32(ddlState.SelectedValue);
    string CS = ConfigurationManager.ConnectionStrings["SportsActiveConnectionString"].ConnectionString;
    using (SqlConnection con = new SqlConnection(CS))
    {
        con.Open();
        SqlCommand cmd = new SqlCommand("spCities", con);
        cmd.Parameters.AddWithValue("@StatId", StatId);
        cmd.CommandType = CommandType.StoredProcedure;
        SqlDataAdapter da = new SqlDataAdapter(cmd);
        DataSet ds = new DataSet();
        da.Fill(ds);
        ddlCity.DataSource = ds;
        ddlCity.DataTextField = "CityName";
        ddlCity.DataValueField = "CityId";
        ddlCity.DataBind();
    }
    ddlCity.Items.Insert(0, new ListItem("---Select---", "0"));
 ddlCity.SelectedIndex = ddlCity.Items.IndexOf(ddlCity.Items.FindByText(hf_city.Value));

创建另一个绑定cityDropdownlist的方法:

protected void BindCityDropDown(int StatId)
{
    string CS = ConfigurationManager.ConnectionStrings["SportsActiveConnectionString"].ConnectionString;
    using (SqlConnection con = new SqlConnection(CS))
    {
        con.Open();
        SqlCommand cmd = new SqlCommand("spCities", con);
        cmd.Parameters.AddWithValue("@StatId", StatId);
        cmd.CommandType = CommandType.StoredProcedure;
        SqlDataAdapter da = new SqlDataAdapter(cmd);
        DataSet ds = new DataSet();
        da.Fill(ds);
        ddlCity.DataSource = ds;
        ddlCity.DataTextField = "CityName";
        ddlCity.DataValueField = "CityId";
        ddlCity.DataBind();
    }
    ddlCity.Items.Insert(0, new ListItem("---Select---", "0"));
}

在dropdownlistselected index change中调用:

protected void ddlState_SelectedIndexChanged(object sender, EventArgs e)
{
    int StatId = Convert.ToInt32(ddlState.SelectedValue);
    BindCityDropdown(StatId);
}

现在在编辑部分绑定citydropdownlist然后赋值:

ddlState.SelectedIndex = ddlState.Items.IndexOf(ddlState.Items.FindByText(rdr["State"].ToString()));
int StatId = Convert.ToInt32(ddlState.SelectedValue);
BindCityDropdown(StatId);
 ddlCity.SelectedIndex = ddlCity.Items.IndexOf(ddlCity.Items.FindByText(rdr["City"].ToString()));
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