预期参数未提供

Question

我有一个表opbal1在数据库中的字段为sno, voc, date, ledcode, type, amt ,part。
直到我保存它是确定的数据，但是当我在编辑数据得到的错误

The parameterized query '(@voc nvarchar(11),@date nvarchar(10),@ledcode nvarchar(4000),@t' 
expects the parameter '@ledcode', which was not supplied 

我的代码：

protected void Page_Load(object sender, EventArgs e) 
{ 
    if (!IsPostBack) 
    { 
     FirstGrid(); 
    } 
} 
private void FirstGrid() 
{ 
    string sno = Request.QueryString["sno"]; 
    Response.Write(sno); 
    if (sno == null) 
    { 
     DataTable dt = new DataTable(); 
     DataRow dr = null; 
     dt.Columns.Add(new DataColumn("0", typeof(string))); 
     dt.Columns.Add(new DataColumn("1", typeof(string))); 
     dt.Columns.Add(new DataColumn("2", typeof(string))); 
     dt.Columns.Add(new DataColumn("3", typeof(string))); 
     dt.Columns.Add(new DataColumn("4", typeof(string))); 
     dt.Columns.Add(new DataColumn("5", typeof(string))); 
     dt.Columns.Add(new DataColumn("6", typeof(string))); 
     dt.Columns.Add(new DataColumn("7", typeof(string))); 
     dr = dt.NewRow(); 
     dr[0] = string.Empty; 
     dr[1] = string.Empty; 
     dr[2] = string.Empty; 
     dr[3] = string.Empty; 
     dr[4] = string.Empty; 
     dr[5] = string.Empty; 
     dr[6] = string.Empty; 
     dr[7] = string.Empty; 
     dt.Rows.Add(dr); 
     ViewState["CurrentTable"] = dt; 
     grvOpbal.DataSource = dt; 
     grvOpbal.DataBind(); 
    } 
    else 
    { 
     Response.Write(Session["flag"]); 
     if (Session["flag"] == "2" || Session["flag"] == "3") 
     { 
      conn.Open(); 
      hdnFlag.Value = Session["flag"].ToString(); 
      btnSave.Enabled = true; 
      SqlCommand cmd = new SqlCommand("select * from opbal1 where sno=@sno", conn); 
      SqlDataAdapter da = new SqlDataAdapter(); 
      da.SelectCommand = cmd; 
      cmd.Parameters.AddWithValue("@sno", sno); 
      DataTable dt = new DataTable(); 
      da.Fill(dt); 
      grvOpbal.DataSource = dt; 
      ViewState["CurrentTable"] = dt; 
      grvOpbal.DataBind(); 
      int i = 0; 
      foreach (DataRow row in dt.Rows) 
      { 
       Label lblSno = (Label)grvOpbal.Rows[i].Cells[0].FindControl("lblSno"); 
       Label lblSrNumber = (Label)grvOpbal.Rows[i].Cells[1].FindControl("lblSrNumber"); 
       DropDownList ddlLedCode = (DropDownList)grvOpbal.Rows[i].Cells[2].FindControl("ddlLedCode"); 
       TextBox txtType = (TextBox)grvOpbal.Rows[i].Cells[3].FindControl("txtType"); 
       TextBox txtAmt = (TextBox)grvOpbal.Rows[i].Cells[4].FindControl("txtAmt"); 
       TextBox txtPart = (TextBox)grvOpbal.Rows[i].Cells[5].FindControl("txtPart"); 
       TextBox txtVoc = (TextBox)grvOpbal.Rows[i].Cells[6].FindControl("txtVoc"); 
       TextBox txtDate = (TextBox)grvOpbal.Rows[i].Cells[7].FindControl("txtDate"); 

       lblSrNumber.Text = Convert.ToInt32(i + 1).ToString(); 
       lblSno.Text = row[0].ToString(); 
       txtVoc.Text = row[1].ToString(); 
       txtDate.Text = row[2].ToString(); 
       ddlLedCode.SelectedValue = row[3].ToString(); 
       txtType.Text = row[4].ToString(); 
       if (txtType.Text == "D" || txtType.Text == "d") 
       { 
        txtAmt.BackColor = System.Drawing.Color.Red; 
       } 
       else 
       { 
        txtAmt.BackColor = System.Drawing.Color.Blue; 
       } 
       txtAmt.Text = row[5].ToString(); 
       txtPart.Text = row[6].ToString(); 
       i++; 
      } 
     } 
    } 
} 
private void SetRowData() 
{ 
    int rowIndex = 0; 
    if (ViewState["CurrentTable"] != null) 
    { 
     DataTable dtCurrentTable = (DataTable)ViewState["CurrentTable"]; 
     DataRow drCurrentRow = null; 
     if (dtCurrentTable.Rows.Count > 0) 
     { 
      for (int i = 1; i <= dtCurrentTable.Rows.Count; i++) 
      { 
       Label lblSno = (Label)grvOpbal.Rows[rowIndex].Cells[1].FindControl("lblSno"); 
       Label lblSrNumber = (Label)grvOpbal.Rows[rowIndex].Cells[2].FindControl("lblSrNumber"); 
       DropDownList ddlLedCode = (DropDownList)grvOpbal.Rows[rowIndex].Cells[3].FindControl("ddlLedCode"); 
       TextBox txtType = (TextBox)grvOpbal.Rows[rowIndex].Cells[4].FindControl("txtType"); 
       TextBox txtAmt = (TextBox)grvOpbal.Rows[rowIndex].Cells[5].FindControl("txtAmt"); 
       TextBox txtPart = (TextBox)grvOpbal.Rows[rowIndex].Cells[6].FindControl("txtPart"); 
       TextBox txtVoc = (TextBox)grvOpbal.Rows[rowIndex].Cells[7].FindControl("txtVoc"); 
       TextBox txtDate = (TextBox)grvOpbal.Rows[rowIndex].Cells[8].FindControl("txtDate"); 
       if (txtType.Text == "D") 
       { 
        //txtType.Attributes.Add("OnFocus", "return OnFocus()"); 
        txtAmt.BackColor = System.Drawing.Color.Red; 
       } 
       else 
       { 
        txtAmt.BackColor = System.Drawing.Color.Blue; 
       } 
       drCurrentRow = dtCurrentTable.NewRow(); 
       dtCurrentTable.Rows[i - 1][0] = lblSno.Text; 
       dtCurrentTable.Rows[i - 1][1] = txtVoc.Text; 
       dtCurrentTable.Rows[i - 1][2] = txtDate.Text; 
       dtCurrentTable.Rows[i - 1][3] = ddlLedCode.SelectedValue; 
       dtCurrentTable.Rows[i - 1][4] = txtType.Text; 
       dtCurrentTable.Rows[i - 1][5] = txtAmt.Text; 
       dtCurrentTable.Rows[i - 1][6] = txtPart.Text; 
       // dtCurrentTable.Rows[i - 1][7] = 
       lblSrNumber.Text = i.ToString(); 

       rowIndex++; 
      } 
      ViewState["CurrentTable"] = dtCurrentTable; 
     } 
    } 
    else 
    { 
     Response.Write("Viewstate is null"); 
    } 
} 
protected void btnSave_Click(object sender, EventArgs e) 
{ 
    SetRowData(); 
    conn.Open(); 

    DataTable table = ViewState["CurrentTable"] as DataTable; 
    if (table != null) 
    { 
     foreach (DataRow row in table.Rows) 
     { 
      int j = 1; 
      string lblSno = row.ItemArray[0] as string; 
      string txtVoc = row.ItemArray[1] as string; 
      string txtDate = row.ItemArray[2] as string; 
      //string lblSrNumber = row.ItemArray[1] as string; 
      string ddlLedCode = row.ItemArray[3] as string; 
      string txtType = row.ItemArray[4] as string; 
      string txtAmt = row.ItemArray[5] as string; 
      string txtPart = row.ItemArray[6] as string; 
      string lblSrNumber = j.ToString(); 
      j++; 
      if (hdnFlag.Value == "1") 
      { 
       string sql1="insert into opbal1 values(@voc,@date,@ledcode,@type,@amt,@part)"; 
       SqlCommand cmd2 = new SqlCommand(sql1, conn); 
       cmd2.Parameters.AddWithValue("@voc", mmvoc); 
       cmd2.Parameters.AddWithValue("@date", today); 
       cmd2.Parameters.AddWithValue("@ledcode", ddlLedCode); 
       cmd2.Parameters.AddWithValue("@type", txtType); 
       cmd2.Parameters.AddWithValue("@amt", txtAmt); 
       cmd2.Parameters.AddWithValue("@part", "opbal"); 
       cmd2.ExecuteNonQuery(); 
      } 
      else if (hdnFlag.Value == "2") 
      { 
       string today = DateTime.Now.ToString("yyyy-dd-M");  
       string sql = "update opbal1 set voc=@voc,date=@date,"; 
       sql += "ledcode=@ledcode,type=@type,amt=@amt,part=@part where sno=@sno"; 
       SqlCommand cmd = new SqlCommand(sql, conn); 
       cmd.Parameters.AddWithValue("@voc", txtVoc); 
       cmd.Parameters.AddWithValue("@date", today); 
       cmd.Parameters.AddWithValue("@ledcode", ddlLedCode); 
       cmd.Parameters.AddWithValue("@type", txtType); 
       cmd.Parameters.AddWithValue("@amt",txtAmt); 
       cmd.Parameters.AddWithValue("@part", "opbal"); 
       cmd.Parameters.AddWithValue("@sno", lblSno); 
       cmd.ExecuteNonQuery(); 
       btnSave.Enabled = false; 
      } 
     } 
    } 
} 

Answer 1

我觉得你的问题很可能是的ddlLedCode值为空，因为空不作为有效值处理，你需要通过DBNull.Value在这种情况下： -

if(ddlLedCode != null) 
    cmd.Parameters.AddWithValue("@ledcode", ddlLedCode); 
else 
    cmd.Parameters.AddWithValue("@ledcode", DBNull.Value); 

另外，请read我们可以停止使用AddWithValue吗？

所以，这会更好： -

if (ddlLedCode != null) 
    cmd.Parameters.Add("@ledcode", SqlDbType.NVarChar).Value = ddlLedCode; 
else 
    cmd.Parameters.Add("@ledcode", SqlDbType.NVarChar).Value = DBNull.Value; 

Answer 2

foreach (DataRow row in table.Rows) 
       { 
        int j = 1; 
        string lblSno = row[0].ToString(); 
        string txtVoc = row[1].ToString(); 
        string txtDate = row[2].ToString(); 
        //string lblSrNumber = row.ItemArray[1] as string; 
        string ddlLedCode = row[3].ToString(); 

        string txtType = row[4].ToString(); 
        string txtAmt = row[5].ToString(); 
        string txtPart = row[6].ToString(); 
} 

而不是使用“row.ItemArray [1]为字符串”我已经使用了上述发言，所以我没有得到错误