如何通过选择下拉列表将数据库值放入文本框中 [英] How to take database value into text box by selecting dropdownlist
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问题描述
我正在使用dropdownlist并且有从数据库中恢复的项目,我的问题是该项目选择项目值将显示在文本框中的任何一项?
< b>我尝试了什么:
受保护 void DropDownList1_SelectedIndexChanged( object sender,EventArgs e)
{
SqlConnection con1 = new SqlConnection( 数据源= XENORIX8- PC;初始目录= xenorix;用户ID = ******;密码= *****);
SqlCommand cmd1 = new SqlCommand( select item_price from quantity where item_name =' + DropDownList1.SelectedItem.Text + ' ,con1);
SqlDataAdapter sda1 = new SqlDataAdapter(cmd1);
DataTable dt1 = new DataTable();
sda1.Fill(dt1);
TextBox1.Text = dt1.Rows [ 0 ]。ToString();
}
这是否正确?如果错误请发送任何线索或代码
解决方案
在最后一行使用下面的代码
TextBox1.Text = dt1.Rows [ 0 ] [ 0 ]。ToString();
试试这个
protected void DropDownList1_SelectedIndexChanged( object sender,EventArgs e)
{
SqlConnection con1 = new SqlConnection( 您的连接字符串);
SqlCommand cmd1 = new SqlCommand( select item_price from quantity where item_name = @ item,con1);
cmd1.Parameters.Add( @ item,DropDownList1.SelectedItem.Text);
SqlDataAdapter sda1 = new SqlDataAdapter(cmd1);
DataTable dt1 = new DataTable();
sda1.Fill(dt1);
if (dt1.Rows.Count > 0 ) // 验证以避免索引异常。
TextBox1.Text = dt1.Rows [ 0 ] [ item_price< /跨度>]的ToString(); // 定义列名
}
I am using dropdownlist and that has item retriveing from database, my question is that item select any one item that item value will display at text box?
What I have tried:
protected void DropDownList1_SelectedIndexChanged(object sender, EventArgs e)
{
SqlConnection con1 = new SqlConnection("Data Source=XENORIX8-PC;Initial Catalog=xenorix;User ID=******;Password=*****");
SqlCommand cmd1 = new SqlCommand("select item_price from quantity where item_name='" + DropDownList1.SelectedItem.Text + "'", con1);
SqlDataAdapter sda1 = new SqlDataAdapter(cmd1);
DataTable dt1 = new DataTable();
sda1.Fill(dt1);
TextBox1.Text = dt1.Rows[0].ToString();
}
Is this correct or not?, If its wrong please send any clue or code
解决方案
use below code in last line
TextBox1.Text = dt1.Rows[0][0].ToString();
Try this
protected void DropDownList1_SelectedIndexChanged(object sender, EventArgs e) { SqlConnection con1 = new SqlConnection("Your Connection string"); SqlCommand cmd1 = new SqlCommand("select item_price from quantity where item_name=@item", con1); cmd1.Parameters.Add("@item", DropDownList1.SelectedItem.Text); SqlDataAdapter sda1 = new SqlDataAdapter(cmd1); DataTable dt1 = new DataTable(); sda1.Fill(dt1); if (dt1.Rows.Count > 0) // validate for avoiding index exception. TextBox1.Text = dt1.Rows[0]["item_price"].ToString(); // define the column name }
You should be aware of SQL Injection[^] when hardcoding the SQl Statemetns
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