组合框绑定问题？ [英] Combo box binding problem?

问题描述

有三个组合框控件并基于第一个组合框值数据绑定到组合框2并基于第二个组合框2值数据绑定到第三个组合框..我的问题是组合记录是否没有组合值框3然而它显示另一条记录的价值，直到匹配才更改



i还不知道这个问题的任何解决方案...

请帮帮我..



我尝试过：

there are three combo box controls and based on first combo box value data bind to combo box 2 and based on second combo box 2 value data bind to third combo box..my question is if the combination record has no value for combo box 3 and yet it is displaying value form another record and not changing until it is matched

i haven't known any solution for this problem...
please help me..

What I have tried:

internal void bindcompname()
        {
            cmd = new SqlCommand("select CompName from company",conn);
            SqlDataAdapter da = new SqlDataAdapter(cmd);
            DataTable dt = new DataTable();
            da.Fill(dt);
            DataRow dr = dt.NewRow();
            comboscname.DisplayMember = "CompName";
            comboscname.DataSource = dt;
            comboscname.DropDownStyle = ComboBoxStyle.DropDownList;
        }
        private void comboscname_SelectedIndexChanged_1(object sender, EventArgs e)
        {
            cmd = new SqlCommand("select model.ModNum from model inner join company on model.CompName=company.CompName where model.CompName=@cname",conn);
            cmd.Parameters.AddWithValue("@cname",comboscname.Text);
            SqlDataAdapter da = new SqlDataAdapter(cmd);
            DataTable dt = new DataTable();
            da.Fill(dt);
            DataRow dr = dt.NewRow();
            combosmnumber.DisplayMember = "ModNum";
            combosmnumber.DataSource = dt;
            combosmnumber.DropDownStyle = ComboBoxStyle.DropDownList;
        }
        private void combosmnumber_SelectedIndexChanged_1(object sender, EventArgs e)
        {
            cmd = new SqlCommand("select mobile.IMEINo from mobile inner join model on model.ModId=mobile.ModId inner join company c on c.CompName=mobile.CompName where model.ModNum=@mid and mobile.Status=@sts", conn);
            cmd.Parameters.AddWithValue("@mid", combosmnumber.Text);
            cmd.Parameters.AddWithValue("@sts", "NotSold");
            SqlDataAdapter da = new SqlDataAdapter(cmd);
            DataTable dt = new DataTable();
            da.Fill(dt);
            DataRow dr = dt.NewRow();
            combosimeinumber.DisplayMember = "IMEINo";
            combosimeinumber.DataSource = dt;
            combosimeinumber.DropDownStyle = ComboBoxStyle.DropDownList;
        }

推荐答案

检查一下：

使用C＃.Net 在Windows窗体（WinForms）应用程序中级联ComboBox [< a href =https://www.aspforums.net/Threads/828656/Cascading-ComboBox-in-Windows-Forms-WinForms-application-using-C-Net/\"target =_ blanktitle =New Window > ^ ]

级联Winforms Windows窗体中的ComboBox C＃VB.NET [ ^ ]

Check this:
Cascading ComboBox in Windows Forms (WinForms) application using C# .Net[^]
Cascading ComboBox In Winforms Windows Forms C# VB.NET[^]

Quote：

internal void bindcompname（）

{

cmd = new SqlCommand（select compName from company，conn）;

SqlDataAdapter da = new SqlDataAdapter（cmd）;

DataTable dt = new DataTable（）;

da.Fill（dt）;

DataRow dr = dt.NewRow（）;

comboscname.DisplayMember =CompName;

comboscname.DataSource = dt;

comboscname.DropDownStyle = ComboBoxStyle.DropDownList;

}

private void comboscname_SelectedIndexChanged_1（object sender，EventArgs e）

{

cmd = new SqlCommand（select model.ModNum from model inner join company on model.CompName = company.CompName where model.CompName=@cname，conn）;

cmd.Parameters.AddWithValue （@cname，comboscname.Text）;

SqlDataAdapter da = new SqlDataAdapter（cmd）;

DataTable dt = new DataTable（）;

da.Fill（dt）;

DataRow dr = dt.NewRow（）;

combosmnumber.DisplayMember =ModNum;

combosmnumber.DataSource = dt;

combosmnumber.DropDownStyle = ComboBoxStyle.DropDownList;

}

private void combosmnumber_SelectedIndexChanged_1（object sender，EventArgs e）

{

cmd = new SqlCommand（从模型上的移动内连接模型中选择mobile.IMEINo。 modId = mobile.ModId内部联接公司c在c.CompName = mobile.CompName，其中model.ModNum =@mid和mobile.Status=@sts，conn）;

cmd.Parameters.AddWithValue（ @mid，combosmnumber.Text）;

cmd.Parameters.AddWithValue（@ sts，NotSold）;

SqlDataAdapter da = new SqlDataAdapter（cmd） ;

DataTable dt = new DataTable（）;

da.Fill（dt）;

DataRow dr = dt.NewRow（）;

combosimeinumber.DisplayMember =IMEINo;

combosimeinumber.DataSource = dt;

combosimeinumber.DropDownStyle = ComboBoxStyle.DropDownList;

}

internal void bindcompname()
{
cmd = new SqlCommand("select CompName from company",conn);
SqlDataAdapter da = new SqlDataAdapter(cmd);
DataTable dt = new DataTable();
da.Fill(dt);
DataRow dr = dt.NewRow();
comboscname.DisplayMember = "CompName";
comboscname.DataSource = dt;
comboscname.DropDownStyle = ComboBoxStyle.DropDownList;
}
private void comboscname_SelectedIndexChanged_1(object sender, EventArgs e)
{
cmd = new SqlCommand("select model.ModNum from model inner join company on model.CompName=company.CompName where model.CompName=@cname",conn);
cmd.Parameters.AddWithValue("@cname",comboscname.Text);
SqlDataAdapter da = new SqlDataAdapter(cmd);
DataTable dt = new DataTable();
da.Fill(dt);
DataRow dr = dt.NewRow();
combosmnumber.DisplayMember = "ModNum";
combosmnumber.DataSource = dt;
combosmnumber.DropDownStyle = ComboBoxStyle.DropDownList;
}
private void combosmnumber_SelectedIndexChanged_1(object sender, EventArgs e)
{
cmd = new SqlCommand("select mobile.IMEINo from mobile inner join model on model.ModId=mobile.ModId inner join company c on c.CompName=mobile.CompName where model.ModNum=@mid and mobile.Status=@sts", conn);
cmd.Parameters.AddWithValue("@mid", combosmnumber.Text);
cmd.Parameters.AddWithValue("@sts", "NotSold");
SqlDataAdapter da = new SqlDataAdapter(cmd);
DataTable dt = new DataTable();
da.Fill(dt);
DataRow dr = dt.NewRow();
combosimeinumber.DisplayMember = "IMEINo";
combosimeinumber.DataSource = dt;
combosimeinumber.DropDownStyle = ComboBoxStyle.DropDownList;
}

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