两个下拉列表验证 [英] Two dropdown list validations
本文介绍了两个下拉列表验证的处理方法，对大家解决问题具有一定的参考价值，需要的朋友们下面随着小编来一起学习吧！
问题描述
我在dxe中有4个dwon列表：ASPxComboBox。当我点击第二个下拉列表而不选择第一个下拉列表时它将显示为plase select 1st drop down.how我可以编写逻辑请告诉我
我是什么尝试过：
I have 4 drop dwon lists in dxe:ASPxComboBox. when i click 2nd dropdown with out selecting 1st dropdown it will display as plase select 1st drop down.how can i write the logic please tell me
What I have tried:
推荐答案
你好
如果你的意思是说你正在寻找Cascade DropDownList ，代码是：
CodeBehind：
Hello
If you mean you are looking for Cascade DropDownList, the code is :
CodeBehind:
protected void Page_Load(object sender, EventArgs e)
{
gvProduct.DataSourceID = ldsProduct.ID;
if (!IsPostBack)
{
ddlType.AppendDataBoundItems = true;
string strConnection = "Data Source =Ali-HP;Database=EzBuy;Integrated Security=yes";
using (SqlConnection Connection = new SqlConnection(strConnection))
{
String strQuery = "select TypeID, TypeName from PrType";
SqlCommand cmd = new SqlCommand();
cmd.CommandType = CommandType.Text;
cmd.CommandText = strQuery;
cmd.Connection = Connection;
try
{
cmd.Connection.Open();
ddlType.DataSource = cmd.ExecuteReader();
ddlType.DataTextField = "TypeName";
ddlType.DataValueField = "TypeID";
ddlType.DataBind();
}
catch (Exception ex)
{
throw ex;
}
finally
{
cmd.Connection.Close();
cmd.Connection.Dispose();
}
}
}
}
protected void ddlType_SelectedIndexChanged(object sender, EventArgs e)
{
ddlSubType.Items.Clear();
ddlSubType.Items.Add(new ListItem("select Product", ""));
ddlCompany.Items.Clear();
ddlCompany.Items.Add(new ListItem("select company", ""));
ddlSubType.AppendDataBoundItems = true;
string strConnection = "Data Source =Ali-HP;Database=EzBuy;Integrated Security=yes";
using (SqlConnection Connection = new SqlConnection(strConnection))
{
String strQuery = "select SubTypeID, SubTypeName from PrSubType where TypeID=@TypeID ";
SqlCommand cmd = new SqlCommand();
cmd.Parameters.AddWithValue("@TypeID", ddlType.SelectedItem.Value);
cmd.CommandType = CommandType.Text;
cmd.CommandText = strQuery;
cmd.Connection = Connection;
try
{
cmd.Connection.Open();
ddlSubType.DataSource = cmd.ExecuteReader();
ddlSubType.DataTextField = "SubTypeName";
ddlSubType.DataValueField = "SubTypeID";
ddlSubType.DataBind();
if (ddlSubType.Items.Count > 1)
{
ddlSubType.Enabled = true;
}
else
{
ddlSubType.Enabled = false;
ddlCompany.Enabled = false;
}
}
catch (Exception ex)
{
throw ex;
}
finally
{
cmd.Connection.Close();
cmd.Connection.Dispose();
}
}
}
protected void ddlSubType_SelectedIndexChanged(object sender, EventArgs e)
{
ddlOS.Items.Clear();
ddlOS.Items.Add(new ListItem("select os", ""));
ddlOS.AppendDataBoundItems = true;
string strConnection = "Data Source =Ali-HP;Database=EzBuy;Integrated Security=yes";
using (SqlConnection Connection = new SqlConnection(strConnection))
{
String strQuery = "select OSID, OSName from PrOS where TypeID=@TypeID ";
SqlCommand cmd = new SqlCommand();
cmd.Parameters.AddWithValue("@TypeID", ddlType.SelectedItem.Value);
cmd.CommandType = CommandType.Text;
cmd.CommandText = strQuery;
cmd.Connection = Connection;
try
{
cmd.Connection.Open();
ddlOS.DataSource = cmd.ExecuteReader();
ddlOS.DataTextField = "OSName";
ddlOS.DataValueField = "OSID";
ddlOS.DataBind();
if (ddlOS.Items.Count > 1)
{
ddlOS.Enabled = true;
}
else
{
ddlOS.Enabled = false;
}
}
catch (Exception ex)
{
throw ex;
}
finally
{
cmd.Connection.Close();
cmd.Connection.Dispose();
}
}
}
protected void ddlOS_SelectedIndexChanged(object sender, EventArgs e)
{
ddlCompany.Items.Clear();
ddlCompany.Items.Add(new ListItem("select company", ""));
ddlCompany.AppendDataBoundItems = true;
string strConnection = "Data Source =Ali-HP;Database=EzBuy;Integrated Security=yes";
using (SqlConnection Connection = new SqlConnection(strConnection))
{
String strQuery = "select CompanyID, CompanyName from PrCompany where TypeID=@TypeID ";
SqlCommand cmd = new SqlCommand();
cmd.Parameters.AddWithValue("@TypeID", ddlType.SelectedItem.Value);
cmd.CommandType = CommandType.Text;
cmd.CommandText = strQuery;
cmd.Connection = Connection;
try
{
cmd.Connection.Open();
ddlCompany.DataSource = cmd.ExecuteReader();
ddlCompany.DataTextField = "CompanyName";
ddlCompany.DataValueField = "CompanyID";
ddlCompany.DataBind();
if (ddlCompany.Items.Count > 1)
{
ddlCompany.Enabled = true;
}
else
{
ddlCompany.Enabled = false;
}
}
catch (Exception ex)
{
throw ex;
}
finally
{
cmd.Connection.Close();
cmd.Connection.Dispose();
}
}
}
protected void ddlCompany_SelectedIndexChanged(object sender, EventArgs e)
{
}
描述：当你想选择第二个DDL时，你必须先设置第一个DDL的值。第二个DDL被禁用，直到您选择第一个DDL的值。
希望它能解决您的问题
最好的问候
description: when you want to select 2nd DDL, you have to set a value for the 1st one first. the 2nd DDL is disabled until you have selected the value for 1st one.
hope it solve your problem
best regards
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