在两个连续的下拉列表中显示结果时出现问题 [英] Problem in displaying result from two successive drop down list
本文介绍了在两个连续的下拉列表中显示结果时出现问题的处理方法，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
设计:
Design:
<asp:Button ID="btnselect" runat="server" Height="30px"
onclick="btnselect_Click" Text="Select" Width="69px" />
<asp:DropDownList ID="BranchList" runat="server" Height="60px" Width="140px"
onselectedindexchanged="BranchList_SelectedIndexChanged">
</asp:DropDownList>
<asp:DropDownList ID="StudentList" runat="server" Height="60px" Width="140px"
onselectedindexchanged="StudentList_SelectedIndexChanged">
</asp:DropDownList>
<table style="width: 100%">
<tr>
<td>
</td>
<td>
</td>
</tr>
<tr>
<td>
<asp:Label ID="lblname" runat="server" Text="Name"></asp:Label>
</td>
<td>
<asp:TextBox ID="txtname" runat="server" Height="20px" Width="150px"></asp:TextBox>
</td>
</tr>
<tr>
<td>
<asp:Label ID="lblroll_no" runat="server" Text="Roll No"></asp:Label>
</td>
<td>
<asp:TextBox ID="txtroll_No" runat="server" Height="20px" Width="150px"></asp:TextBox>
</td>
</tr>
<tr>
<td>
<asp:Label ID="lblbranch" runat="server" Text="Branch"></asp:Label>
</td>
<td>
<asp:DropDownList ID="BranchList0" runat="server" Height="60px" Width="140px"
onselectedindexchanged="BranchList_SelectedIndexChanged">
</asp:DropDownList>
</td>
</tr>
<tr>
<td>
<asp:Label ID="lblrecruiter" runat="server" Text="Recruiter"></asp:Label>
</td>
<td>
<asp:TextBox ID="txtrecruiter" runat="server"
Height="20px" Width="150px"></asp:TextBox>
</td>
</tr>
<tr>
<td>
<asp:Label ID="lblpackage" runat="server" Text="Package"></asp:Label>
</td>
<td>
<asp:TextBox ID="txtpackage" runat="server" Height="20px" Width="150px"></asp:TextBox>
</td>
</tr>
<tr>
<td>
</td>
<td>
</td>
</tr>
<tr>
<td>
</td>
<td>
<asp:Button ID="btnsubmit" runat="server" onclick="btnsubmit_Click"
Text="Submit" />
</td>
</tr>
</table>
编码:
Coding:
protected void Page_Load(object sender, EventArgs e)
{
if (!IsPostBack)
{
loadBranchList();
loadStudentList();
loadBranchList0();
}
}
protected void loadBranchList()
{
SqlConnection CON;
SqlCommand COM;
SqlDataReader READER;
string ConnectionString = ConfigurationManager.ConnectionStrings["TnP"].ConnectionString;
CON = new SqlConnection(ConnectionString);
COM = new SqlCommand("Select Branches from Branches", CON);
try
{
CON.Open();
READER = COM.ExecuteReader();
BranchList.DataSource = READER;
BranchList.DataValueField = "Branches";
BranchList.DataBind();
READER.Close();
}
catch
{
CON.Close();
}
}
protected void loadBranchList0()
{
SqlConnection CON;
SqlCommand COM;
SqlDataReader READER;
string ConnectionString = ConfigurationManager.ConnectionStrings["TnP"].ConnectionString;
CON = new SqlConnection(ConnectionString);
COM = new SqlCommand("Select Branches from Branches", CON);
try
{
CON.Open();
READER = COM.ExecuteReader();
BranchList0.DataSource = READER;
BranchList0.DataValueField = "Branches";
BranchList0.DataBind();
READER.Close();
}
catch
{
CON.Close();
}
}
protected void loadStudentList()
{
if (!IsPostBack)
{
SqlConnection CON;
SqlCommand COM;
SqlDataReader READER;
string ConnectionString = ConfigurationManager.ConnectionStrings["TnP"].ConnectionString;
CON = new SqlConnection(ConnectionString);
if (BranchList.Text == "ECE")
{
COM = new SqlCommand("Select Name,Roll_No from [ECE(07-11)]", CON);
}
else if (BranchList.Text == "CSE")
{
COM = new SqlCommand("Select Name,Roll_No from [CSE(07-11)]", CON);
}
else if (BranchList.Text == "IT")
{
COM = new SqlCommand("Select Name,Roll_No from [IT(07-11)]", CON);
}
else if (BranchList.Text == "CE")
{
COM = new SqlCommand("Select Name,Roll_No from [CE(07-11)]", CON);
}
else if (BranchList.Text == "EE")
{
COM = new SqlCommand("Select Name,Roll_No from [EE(07-11)]", CON);
}
else if (BranchList.Text == "ME")
{
COM = new SqlCommand("Select Name,Roll_No from [ME(07-11)]", CON);
}
//else if (BranchList.Text == "PE")
{
COM = new SqlCommand("Select Name,Roll_No from [PE(07-11)]", CON);
}
//else
//{
// COM = new SqlCommand("Select Name,Roll_No from [MBA(07-11)]", CON);
//}
CON.Open();
READER = COM.ExecuteReader();
StudentList.DataSource = READER;
StudentList.DataValueField = "Roll_No";
StudentList.DataTextField = "Name";
StudentList.DataBind();
READER.Close();
CON.Close();
}
}
protected void btnsubmit_Click(object sender, EventArgs e)
{
{
SqlConnection CON;
SqlCommand COM;
CON = new SqlConnection(ConfigurationManager.ConnectionStrings["TnP"].ConnectionString);
if (BranchList0.Text == "ECE")
{
COM = new SqlCommand("INSERT INTO [ECE(07-11)] (Name,Roll_No,Branch,Recruiter,Package) VALUES (@Name,@Roll_No,@Branch,@Recruiter,@Package)", CON);
COM.Parameters.Add("@Name", System.Data.SqlDbType.NChar, 50);
COM.Parameters["@Name"].Value = txtname.Text;
COM.Parameters.Add("@Roll_No", System.Data.SqlDbType.Int);
COM.Parameters["@Roll_No"].Value = Convert.ToInt32(txtroll_No.Text);
COM.Parameters.Add("@Branch", System.Data.SqlDbType.NChar, 50);
COM.Parameters["@Branch"].Value = BranchList0.Text;
COM.Parameters.Add("@Recruiter", System.Data.SqlDbType.NChar, 50);
COM.Parameters["@Recruiter"].Value = txtrecruiter.Text;
COM.Parameters.Add("@Package", System.Data.SqlDbType.NChar, 50);
COM.Parameters["@Package"].Value = txtpackage.Text;
}
else if (BranchList0.Text == "CSE")
{
COM = new SqlCommand("INSERT INTO [CSE(07-11)] (Name,Roll_No,Branch,Recruiter,Package) VALUES (@Name,@Roll_No,@Branch,@Recruiter,@Package)", CON);
COM.Parameters.Add("@Name", System.Data.SqlDbType.NChar, 50);
COM.Parameters["@Name"].Value = txtname.Text;
COM.Parameters.Add("@Roll_No", System.Data.SqlDbType.Int);
COM.Parameters["@Roll_No"].Value = Convert.ToInt32(txtroll_No.Text);
COM.Parameters.Add("@Branch", System.Data.SqlDbType.NChar, 50);
COM.Parameters["@Branch"].Value = BranchList0.Text;
COM.Parameters.Add("@Recruiter", System.Data.SqlDbType.NChar, 50);
COM.Parameters["@Recruiter"].Value = txtrecruiter.Text;
COM.Parameters.Add("@Package", System.Data.SqlDbType.NChar, 50);
COM.Parameters["@Package"].Value = txtpackage.Text;
}
else if (BranchList0.Text == "IT")
{
COM = new SqlCommand("INSERT INTO [IT(07-11)] (Name,Roll_No,Branch,Recruiter,Package) VALUES (@Name,@Roll_No,@Branch,@Recruiter,@Package)", CON);
COM.Parameters.Add("@Name", System.Data.SqlDbType.NChar, 50);
COM.Parameters["@Name"].Value = txtname.Text;
COM.Parameters.Add("@Roll_No", System.Data.SqlDbType.Int);
COM.Parameters["@Roll_No"].Value = Convert.ToInt32(txtroll_No.Text);
COM.Parameters.Add("@Branch", System.Data.SqlDbType.NChar, 50);
COM.Parameters["@Branch"].Value = BranchList0.Text;
COM.Parameters.Add("@Recruiter", System.Data.SqlDbType.NChar, 50);
COM.Parameters["@Recruiter"].Value = txtrecruiter.Text;
COM.Parameters.Add("@Package", System.Data.SqlDbType.NChar, 50);
COM.Parameters["@Package"].Value = txtpackage.Text;
}
else if (BranchList0.Text == "CE")
{
COM = new SqlCommand("INSERT INTO [CE(07-11)] (Name,Roll_No,Branch,Recruiter,Package) VALUES (@Name,@Roll_No,@Branch,@Recruiter,@Package)", CON);
COM.Parameters.Add("@Name", System.Data.SqlDbType.NChar, 50);
COM.Parameters["@Name"].Value = txtname.Text;
COM.Parameters.Add("@Roll_No", System.Data.SqlDbType.Int);
COM.Parameters["@Roll_No"].Value = Convert.ToInt32(txtroll_No.Text);
COM.Parameters.Add("@Branch", System.Data.SqlDbType.NChar, 50);
COM.Parameters["@Branch"].Value = BranchList0.Text;
COM.Parameters.Add("@Recruiter", System.Data.SqlDbType.NChar, 50);
COM.Parameters["@Recruiter"].Value = txtrecruiter.Text;
COM.Parameters.Add("@Package", System.Data.SqlDbType.NChar, 50);
COM.Parameters["@Package"].Value = txtpackage.Text;
}
else if (BranchList0.Text == "EE")
{
COM = new SqlCommand("INSERT INTO [EE(07-11)] (Name,Roll_No,Branch,Recruiter,Package) VALUES (@Name,@Roll_No,@Branch,@Recruiter,@Package)", CON);
COM.Parameters.Add("@Name", System.Data.SqlDbType.NChar, 50);
COM.Parameters["@Name"].Value = txtname.Text;
COM.Parameters.Add("@Roll_No", System.Data.SqlDbType.Int);
COM.Parameters["@Roll_No"].Value = Convert.ToInt32(txtroll_No.Text);
COM.Parameters.Add("@Branch", System.Data.SqlDbType.NChar, 50);
COM.Parameters["@Branch"].Value = BranchList0.Text;
COM.Parameters.Add("@Recruiter", System.Data.SqlDbType.NChar, 50);
COM.Parameters["@Recruiter"].Value = txtrecruiter.Text;
COM.Parameters.Add("@Package", System.Data.SqlDbType.NChar, 50);
COM.Parameters["@Package"].Value = txtpackage.Text;
}
else if (BranchList0.Text == "ME")
{
COM = new SqlCommand("INSERT INTO [ME(07-11)] (Name,Roll_No,Branch,Recruiter,Package) VALUES (@Name,@Roll_No,@Branch,@Recruiter,@Package)", CON);
COM.Parameters.Add("@Name", System.Data.SqlDbType.NChar, 50);
COM.Parameters["@Name"].Value = txtname.Text;
COM.Parameters.Add("@Roll_No", System.Data.SqlDbType.Int);
COM.Parameters["@Roll_No"].Value = Convert.ToInt32(txtroll_No.Text);
COM.Parameters.Add("@Branch", System.Data.SqlDbType.NChar, 50);
COM.Parameters["@Branch"].Value = BranchList0.Text;
COM.Parameters.Add("@Recruiter", System.Data.SqlDbType.NChar, 50);
COM.Parameters["@Recruiter"].Value = txtrecruiter.Text;
COM.Parameters.Add("@Package", System.Data.SqlDbType.NChar, 50);
COM.Parameters["@Package"].Value = txtpackage.Text;
}
else if (BranchList0.Text == "PE")
{
COM = new SqlCommand("INSERT INTO [PE(07-11)] (Name,Roll_No,Branch,Recruiter,Package) VALUES (@Name,@Roll_No,@Branch,@Recruiter,@Package)", CON);
COM.Parameters.Add("@Name", System.Data.SqlDbType.NChar, 50);
COM.Parameters["@Name"].Value = txtname.Text;
COM.Parameters.Add("@Roll_No", System.Data.SqlDbType.Int);
COM.Parameters["@Roll_No"].Value = Convert.ToInt32(txtroll_No.Text);
COM.Parameters.Add("@Branch", System.Data.SqlDbType.NChar, 50);
COM.Parameters["@Branch"].Value = BranchList0.Text;
COM.Parameters.Add("@Recruiter", System.Data.SqlDbType.NChar, 50);
COM.Parameters["@Recruiter"].Value = txtrecruiter.Text;
COM.Parameters.Add("@Package", System.Data.SqlDbType.NChar, 50);
COM.Parameters["@Package"].Value = txtpackage.Text;
}
else
{
COM = new SqlCommand("INSERT INTO [MBA(07-11)] (Name,Roll_No,Branch,Recruiter,Package) VALUES (@Name,@Roll_No,@Branch,@Recruiter,@Package)", CON);
COM.Parameters.Add("@Name", System.Data.SqlDbType.NChar, 50);
COM.Parameters["@Name"].Value = txtname.Text;
COM.Parameters.Add("@Roll_No", System.Data.SqlDbType.Int);
COM.Parameters["@Roll_No"].Value = Convert.ToInt32(txtroll_No.Text);
COM.Parameters.Add("@Branch", System.Data.SqlDbType.NChar, 50);
COM.Parameters["@Branch"].Value = BranchList0.Text;
COM.Parameters.Add("@Recruiter", System.Data.SqlDbType.NChar, 50);
COM.Parameters["@Recruiter"].Value = txtrecruiter.Text;
COM.Parameters.Add("@Package", System.Data.SqlDbType.NChar, 50);
COM.Parameters["@Package"].Value = txtpackage.Text;
}
CON.Open();
COM.ExecuteNonQuery();
CON.Close();
}
}
protected void btnselect_Click(object sender, EventArgs e)
{
SqlConnection CON;
SqlCommand COM;
SqlDataReader READER;
string ConnectionString = ConfigurationManager.ConnectionStrings["TnP"].ConnectionString;
CON = new SqlConnection(ConnectionString);
if (BranchList.Text == "ECE" && (!IsPostBack) )
{
COM = new SqlCommand("SELECT Name,Roll_No,Branch,Recruiter,Package FROM [ECE(07-11)] " + "WHERE Roll_No= @Roll_No", CON);
COM.Parameters.Add("@Roll_No", System.Data.SqlDbType.Int);
COM.Parameters["@Roll_No"].Value = StudentList.SelectedItem.Value;
CON.Open();
READER = COM.ExecuteReader();
if (READER.Read())
{
txtname.Text = READER["Name"].ToString();
txtroll_No.Text = READER["Roll_No"].ToString();
BranchList0.Text = READER["Branch"].ToString();
txtrecruiter.Text = READER["Recruiter"].ToString();
txtpackage.Text = READER["Package"].ToString();
}
READER.Close();
}
else if (BranchList.Text == "CSE" && (!IsPostBack))
{
COM = new SqlCommand("SELECT Name,Roll_No,Branch,Recruiter,Package FROM [CSE(07-11)] " + "WHERE Roll_No= @Roll_No", CON);
COM.Parameters.Add("@Roll_No", System.Data.SqlDbType.Int);
COM.Parameters["@Roll_No"].Value = StudentList.SelectedItem.Value;
CON.Open();
READER = COM.ExecuteReader();
if (READER.Read())
{
txtname.Text = READER["Name"].ToString();
txtroll_No.Text = READER["Roll_No"].ToString();
BranchList0.Text = READER["Branch"].ToString();
txtrecruiter.Text = READER["Recruiter"].ToString();
txtpackage.Text = READER["Package"].ToString();
}
READER.Close();
}
else if (BranchList.Text == "IT" && (!IsPostBack))
{
COM = new SqlCommand("SELECT Name,Roll_No,Branch,Recruiter,Package FROM [IT(07-11)] " + "WHERE Roll_No= @Roll_No", CON);
COM.Parameters.Add("@Roll_No", System.Data.SqlDbType.Int);
COM.Parameters["@Roll_No"].Value = StudentList.SelectedItem.Value;
CON.Open();
READER = COM.ExecuteReader();
if (READER.Read())
{
txtname.Text = READER["Name"].ToString();
txtroll_No.Text = READER["Roll_No"].ToString();
BranchList0.Text = READER["Branch"].ToString();
txtrecruiter.Text = READER["Recruiter"].ToString();
txtpackage.Text = READER["Package"].ToString();
}
READER.Close();
}
else if (BranchList.Text == "CE" && (!IsPostBack))
{
COM = new SqlCommand("SELECT Name,Roll_No,Branch,Recruiter,Package FROM [CE(07-11)] " + "WHERE Roll_No= @Roll_No", CON);
COM.Parameters.Add("@Roll_No", System.Data.SqlDbType.Int);
COM.Parameters["@Roll_No"].Value = StudentList.SelectedItem.Value;
CON.Open();
READER = COM.ExecuteReader();
if (READER.Read())
{
txtname.Text = READER["Name"].ToString();
txtroll_No.Text = READER["Roll_No"].ToString();
BranchList0.Text = READER["Branch"].ToString();
txtrecruiter.Text = READER["Recruiter"].ToString();
txtpackage.Text = READER["Package"].ToString();
}
READER.Close();
}
else if (BranchList.Text == "EE" && (!IsPostBack))
{
COM = new SqlCommand("SELECT Name,Roll_No,Branch,Recruiter,Package FROM [EE(07-11)] " + "WHERE Roll_No= @Roll_No", CON);
COM.Parameters.Add("@Roll_No", System.Data.SqlDbType.Int);
COM.Parameters["@Roll_No"].Value = StudentList.SelectedItem.Value;
CON.Open();
READER = COM.ExecuteReader();
if (READER.Read())
{
txtname.Text = READER["Name"].ToString();
txtroll_No.Text = READER["Roll_No"].ToString();
BranchList0.Text = READER["Branch"].ToString();
txtrecruiter.Text = READER["Recruiter"].ToString();
txtpackage.Text = READER["Package"].ToString();
}
READER.Close();
}
else if (BranchList.Text == "ME" && (!IsPostBack))
{
COM = new SqlCommand("SELECT Name,Roll_No,Branch,Recruiter,Package FROM [ME(07-11)] " + "WHERE Roll_No= @Roll_No", CON);
COM.Parameters.Add("@Roll_No", System.Data.SqlDbType.Int);
COM.Parameters["@Roll_No"].Value = StudentList.SelectedItem.Value;
CON.Open();
READER = COM.ExecuteReader();
if (READER.Read())
{
txtname.Text = READER["Name"].ToString();
txtroll_No.Text = READER["Roll_No"].ToString();
BranchList0.Text = READER["Branch"].ToString();
txtrecruiter.Text = READER["Recruiter"].ToString();
txtpackage.Text = READER["Package"].ToString();
}
READER.Close();
}
else if (BranchList.Text == "PE" && (!IsPostBack))
{
COM = new SqlCommand("SELECT Name,Roll_No,Branch,Recruiter,Package FROM [PE(07-11)] " + "WHERE Roll_No= @Roll_No", CON);
COM.Parameters.Add("@Roll_No", System.Data.SqlDbType.Int);
COM.Parameters["@Roll_No"].Value = StudentList.SelectedItem.Value;
CON.Open();
READER = COM.ExecuteReader();
if (READER.Read())
{
txtname.Text = READER["Name"].ToString();
txtroll_No.Text = READER["Roll_No"].ToString();
BranchList0.Text = READER["Branch"].ToString();
txtrecruiter.Text = READER["Recruiter"].ToString();
txtpackage.Text = READER["Package"].ToString();
}
READER.Close();
}
else
{
COM = new SqlCommand("SELECT Name,Roll_No,Branch,Recruiter,Package FROM [MBA(07-11)] " + "WHERE Roll_No= @Roll_No", CON);
COM.Parameters.Add("@Roll_No", System.Data.SqlDbType.Int);
COM.Parameters["@Roll_No"].Value = StudentList.SelectedItem.Value;
CON.Open();
READER = COM.ExecuteReader();
if (READER.Read())
{
txtname.Text = READER["Name"].ToString();
txtroll_No.Text = READER["Roll_No"].ToString();
BranchList0.Text = READER["Branch"].ToString();
txtrecruiter.Text = READER["Recruiter"].ToString();
txtpackage.Text = READER["Package"].ToString();
}
READER.Close();
}
}
推荐答案
我在后面的代码中没有找到BranchList_SelectedIndexChanged的任何代码.
此外，您可以考虑 Ajax CascadingDropDown [ google [
I didn''t find any code forBranchList_SelectedIndexChangedin your code behind.
Moreover, you can consider Ajax CascadingDropDown[^]. Use google[^] for samples if interested.
From next time, post only relevant code in your question.
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