我在 C# 中有一个 Windows 窗体，它有 3 个组合框。现在的问题是，当我通过插入的 sql 查询时，它给了我这个错误。请帮我解决错误。这是代码。
namespace login
{
public partial class samplerequisition : Form
{
SqlConnection con = new SqlConnection("Data Source=TH07L019;Initial Catalog=procurement1;Integrated Security=True");
SqlCommand cmd = new SqlCommand();
SqlDataReader rdr;
DataSet dsreqname = new DataSet();
DataSet dsprepname = new DataSet();
DataSet dsauthorizedname = new DataSet();
public samplerequisition()
{
InitializeComponent();
}
bool IsAllValid()
{
if (String.IsNullOrEmpty(txtreqno.Text))
{
return false;
}
else if (String.IsNullOrEmpty(txtexpectedate.Text))
{
return false;
}
else if (String.IsNullOrEmpty(txtcc.Text))
{
return false;
}
else if (String.IsNullOrEmpty(txtbrand.Text))
{
return false;
}
/*else if (String.IsNullOrEmpty(txtprepname.Text))
{
return false;
}
else if (String.IsNullOrEmpty(txtauthorizedname.Text))
{
return false;
}*/
else if (cmbrequisitionname.SelectedItem==null)
{
return false;
}
else if (cmbpreparedname.SelectedItem == null)
{
return false;
}
else if (cmbauthorizedname.SelectedItem == null)
{
return false;
}
else if (Convert.ToString(dtreqdate.Value) == "")
{
return false;
}
else if (Convert.ToString(dtprepdate.Value) == "")
{
return false;
}
else if (Convert.ToString(dtauthorizedate.Value) == "")
{
return false;
}
else
{
return true;
}
}
private void samplerequisition_Load(object sender, EventArgs e)
{
SqlDataAdapter adp = new SqlDataAdapter(cmd);
cmd.Connection = con;
cmd.CommandText = "select * from employee";
adp.Fill(dsreqname,"employee");
cmbrequisitionname.DataSource = dsreqname.Tables["employee"];
cmbrequisitionname.DisplayMember = "fname";
cmbrequisitionname.SelectedIndex = -1;
adp.Fill(dsprepname, "employees");
cmbpreparedname.DataSource = dsprepname.Tables["employees"];
cmbpreparedname.DisplayMember = "fname";
cmbpreparedname.SelectedIndex = -1;
adp.Fill(dsauthorizedname, "employees");
cmbauthorizedname.DataSource = dsauthorizedname.Tables["employees"];
cmbauthorizedname.DisplayMember = "fname";
cmbauthorizedname.SelectedIndex = -1;
}
private void btnsave_Click(object sender, EventArgs e)
{
con.Open();
if (IsAllValid())
{
cmd.CommandText = "insert into samplerequisition(req_no,reqemployee_id,charges,expected_date,reqdate,costcenter_id,specific_brand,preparedemployee_id,prepared_date,authorizedemployee_id,auhtorized_date) values(@req_no,@reqemployee_id,@expected_date,@reqdate,@charges,@costcenter_id,@specific_brand,@preparedemployee_id,@prepared_date,@authorizedemployee_id,@auhtorized_date)";
cmd.CommandType = CommandType.Text;
cmd.Parameters.AddWithValue("@req_no",txtreqno.Text);
cmd.Parameters.AddWithValue("@reqemployee_id",cmbrequisitionname.SelectedValue);
cmd.Parameters.AddWithValue("@expected_date",txtexpectedate.Text );
cmd.Parameters.AddWithValue("@reqdate", dtreqdate.Value);
cmd.Parameters.AddWithValue("@costcenter_id",txtcc.Text);
cmd.Parameters.AddWithValue("@specific_brand",txtbrand.Text);
cmd.Parameters.AddWithValue("@preparedemployee_id",cmbpreparedname.SelectedValue);
cmd.Parameters.AddWithValue("@prepared_date", dtprepdate.Value);
cmd.Parameters.AddWithValue("@authorizedemployee_id",cmbauthorizedname.SelectedValue);
cmd.Parameters.AddWithValue("@auhtorized_date", dtauthorizedate.Value);
if (rdcapex.Checked)
{
cmd.Parameters.AddWithValue("@charges", "Capex");
}
else
{
cmd.Parameters.AddWithValue("@charges", "revenue");
}
cmd.ExecuteNonQuery();
MessageBox.Show("record saved","requisition",MessageBoxButtons.OKCancel,MessageBoxIcon.Information);
}
else
{
MessageBox.Show("error","requisition",MessageBoxButtons.OKCancel,MessageBoxIcon.Error);
con.Close();
}
}
}
}