从数据库中选择查询

本文关键字：查询 选择 数据库 | 更新日期: 2023-09-27 18:20:01

我认为一切都很好，为什么数据没有显示在文本框中。我用了很多次这个代码。那么这里有什么错误呢？我在Visual Studio 2012工作。

string name = comboBox1.SelectedIndex.ToString();
query = "select *from Record Where Name='"+name+"'";
cmd = new SqlCommand(query, con);
con.Open();
SqlDataReader dr = cmd.ExecuteReader();
while (dr.Read())
{
     textBox1.Text =(dr["Items1"].ToString());
     textBox2.Text = (dr["Items1_Charge"].ToString());
     textBox3.Text = (dr["Items2"].ToString());
     textBox4.Text = (dr["Items2_Charge"].ToString());
     textBox5.Text = (dr["Items3"].ToString());
     textBox6.Text = (dr["Items3_Charge"].ToString());
     textBox7.Text = (dr["Items4"].ToString());
     textBox8.Text = (dr["Items4_Charge"].ToString());               
}

从数据库中选择查询

我怀疑*from应该是*from。此外，我建议使用如下所示的where条件的参数，尤其是当有可能嵌入撇号时。另外请注意，我添加了HasRows，所以我们确信有什么东西回来了。我还更改了从ComboBox 获取当前值的方式

public void Sample()
{
    string name = comboBox1.Text;
    query = "select * from Record Where Name= @Name";
    cmd = new SqlCommand(query, con);
    cmd.Parameters.AddWithValue("@Name", name);
    con.Open();
    SqlDataReader dr = cmd.ExecuteReader();
    if (dr.HasRows)
    {
        while (dr.Read())
        {
            textBox1.Text = (dr["Items1"].ToString());
            textBox2.Text = (dr["Items1_Charge"].ToString());
            textBox3.Text = (dr["Items2"].ToString());
            textBox4.Text = (dr["Items2_Charge"].ToString());
            textBox5.Text = (dr["Items3"].ToString());
            textBox6.Text = (dr["Items3_Charge"].ToString());
            textBox7.Text = (dr["Items4"].ToString());
            textBox8.Text = (dr["Items4_Charge"].ToString());
        }
    }
}
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