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c# - 'ExecuteNonQuery：CommandText 属性尚未初始化'初学者在这里

问题描述

我是 sql 和 c# 的新手，我在 executenonquery commandtex 中有错误。我不知道错误在哪里。你们能帮我吗？

private void submitBtn_Click(object sender, EventArgs e)
{
    con.Open();

    string a = "Accept";
    string b = "Reject";
    string queryUpdate1 = "";
    string queryUpdate2 = "";
    int row = DGVLeaves.CurrentCell.RowIndex;


    if (accptBtn.Checked)
    {
        if (type_rdonly.Text == "SL")
        {
            if (ifEmployeeExist(con, emptime_rdonly.Text))
            {
                queryUpdate1 = @"UPDATE [LEAVE_EMP] SET EMP_STATUS ='" + a + "'WHERE [EMP_TIME] ='" + emptime_rdonly.Text + "'";
            }
            queryUpdate2 = "UPDATE LEAVE_ADMIN SET L_SPENT_SL = (L_SPENT_SL + 1), L_REM_SL = (L_REM_SL - 1)";
        }
        if (type_rdonly.Text == "VL")
        {
            if (ifEmployeeExist(con, emptime_rdonly.Text))
            {
                queryUpdate1 = @"UPDATE [LEAVE_EMP] SET EMP_STATUS ='" + a + "'WHERE [EMP_TIME] ='" + emptime_rdonly.Text + "'";
            }
            queryUpdate2 = "UPDATE LEAVE_ADMIN SET L_SPENT_VL = (L_SPENT_VL + 1),L_REM_VL = (L_REM_VL - 1)";
        }
        SqlCommand cmd1 = new SqlCommand(queryUpdate1, con);
        SqlCommand cmd2 = new SqlCommand(queryUpdate2, con);
        cmd2.ExecuteNonQuery();
        cmd1.ExecuteNonQuery();
    }
    if (rejBtn.Checked)
    {
        if (ifEmployeeExist(con, emptime_rdonly.Text))
        {
            queryUpdate1 = @"UPDATE [LEAVE_EMP] SET EMP_STATUS ='" + b + "'WHERE [EMP_TIME] ='" + emptime_rdonly.Text + "'";
        }
        SqlCommand cmd1 = new SqlCommand(queryUpdate1, con);
        cmd1.ExecuteNonQuery();
    }
    con.Close();
}

标签： c#sqlerror-handlingcommand-text

解决方案

我认为 if 子句太多，您可能会在此过程中遗漏一些东西。在执行 ExecuteNonQuery 命令之前尝试调试并查看变量 queryUpdate1 或 queryUpdate2 是否为空。如果它是空的，那应该是原因

我已经为您调整了代码，希望这对您有所帮助

private void submitBtn_Click(object sender, EventArgs e)
    {

        string a = "Accept";
        string b = "Reject";
        string queryUpdate1 = "";
        string queryUpdate2 = "";
        int row = DGVLeaves.CurrentCell.RowIndex;

        if (accptBtn.Checked)
        {
            if (type_rdonly.Text == "SL")
            {
                if (ifEmployeeExist(con, emptime_rdonly.Text))
                {
                    queryUpdate1 = @"UPDATE [LEAVE_EMP] SET EMP_STATUS ='" + a + "'WHERE [EMP_TIME] ='" + emptime_rdonly.Text + "'";
                }
                queryUpdate2 = "UPDATE LEAVE_ADMIN SET L_SPENT_SL = (L_SPENT_SL + 1), L_REM_SL = (L_REM_SL - 1)";
            }
            if (type_rdonly.Text == "VL")
            {
                if (ifEmployeeExist(con, emptime_rdonly.Text))
                {
                    queryUpdate1 = @"UPDATE [LEAVE_EMP] SET EMP_STATUS ='" + a + "'WHERE [EMP_TIME] ='" + emptime_rdonly.Text + "'";
                }
                queryUpdate2 = "UPDATE LEAVE_ADMIN SET L_SPENT_VL = (L_SPENT_VL + 1),L_REM_VL = (L_REM_VL - 1)";
            }
        }

        else if (rejBtn.Checked)
        {
            if (ifEmployeeExist(con, emptime_rdonly.Text))
            {
                queryUpdate1 = @"UPDATE [LEAVE_EMP] SET EMP_STATUS ='" + b + "'WHERE [EMP_TIME] ='" + emptime_rdonly.Text + "'";
            }
        }

        con.Open();

        SqlCommand cmd = new SqlCommand() { Connection = con, CommandType = System.Data.CommandType.Text };
        if (!string.IsNullOrEmpty(queryUpdate1)) {
            cmd.CommandText = queryUpdate1;
            cmd.ExecuteNonQuery();
        }

        if (!string.IsNullOrEmpty(queryUpdate2))
        {
            cmd.CommandText = queryUpdate2;
            cmd.ExecuteNonQuery();
        }

        if (string.IsNullOrEmpty(queryUpdate1) && string.IsNullOrEmpty(queryUpdate2))
        {
            MessageBox.Show("Empty query");
        }

        con.Close();
    }

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