Question

 private void btnCheck_Click(object send, EventArgs ex)
 {      
        string querytxt = @"SELECT Count(itemno) FROM Items WHERE itemno = @itemno";
        SqlConnection cnn = new SqlConnection(@"Data Source=PC80978273\SQLEXPRESS;Initial Catalog=Inventory;User ID=sa;Password=Rmdj1q2w3e!");
        SqlCommand cmd = new SqlCommand(querytxt, cnn);

        cnn.Open();

        cmd.Parameters.AddWithValue("@itemno", txtName.Text);

        int result = (int)cmd.ExecuteScalar();

        if (result > 0)
        {
            btnDelete.Enabled = true;
            SqlConnection conn = new SqlConnection(@"Data Source=PC80978273\SQLEXPRESS;Initial Catalog=Inventory;User ID=sa;Password=Rmdj1q2w3e!");
            SqlCommand cmnd = new SqlCommand("SELECT itemno, categ, name, quant, price FROM Items ", conn);
            conn.Open();
            SqlDataReader dr = cmnd.ExecuteReader();
            if (dr.Read())
            {
                label6.Text = dr.GetValue(0).ToString();
                label1.Text = dr.GetValue(1).ToString();
                label2.Text = dr.GetValue(2).ToString();
                label3.Text = dr.GetValue(3).ToString();
                label4.Text = dr.GetValue(4).ToString();
            }
            txtName.Clear();
            txtName.Enabled = false;
            btnCheck.Enabled = false;
        }
        else
            MessageBox.Show("No data found!");

        cnn.Close();
  }

我在数据库中有两行数据＆＃34; itemno＆＃34;作为我的主键。文本框＆＃34; txtName.Text＆＃34;是数据库中项目编号（itemno）的值。标签的值将取决于txtName.Text的输入。但是，当我点击＆＃34;检查＆＃34;按钮，它只显示第一行。我试过输入＆＃34; itemno＆＃34;的值。在文本框上，但标签仍显示第一行的值。我如何解决此问题以根据＆＃34; itemno＆＃34;更正标签的显示？那是在文本框中输入的？

Answer 1

您应修改查询使用where子句，以便在文本框中输入值的基础上获取所需的行，如：

int val = Convert.ToInt32(txtName.Text);
string strQuery = "SELECT itemno, categ, name, quant, price FROM Items Where itemno = " + val;
SqlCommand cmnd = new SqlCommand(strQuery, conn);

从数据库插入数据后如何更改标签的值？

1 个答案: